Revco

I just did both O2 and coolant temp sensor. If I remember right, it's the larger of all the harnesses on the passenger side...kind of oval like connector...and goes back past the firewall. I think it had three wires, black/white/white...but I'm not looking at mine, so could be wrong. You can follow it up from the intermediate pipe if you have trouble. Just an FYI, I was having O2 codes that were keeping my ECU from throwing a code for the Engine Coolant Temp Sensor, but the sensor "tested" fine. Both needed replacement on my 260K mile Pathy and that O2 sensor's on a recommended 60K mile replacement cycle, just so you know. Temp sensor's only $35 from your local dealership, even cheaper from Courtesy...easy to replace on a 95...it's right past your upper radiator hose on the intake. You will probably have to remove both the sensors to replace the engine temp sensor...the first is the gauge sensor (one wire), the second is your ECU coolant sensor (two wire). You're pretty close to a 100K tune up cycle...might also be wise to check your plugs...or maybe just replace your plugs, wires, cap and rotor. Pretty easy job except for #6, hate that thing. If you haven't owned it since 100K...no telling what was or wasn't done on it.

I wanted to provide an update on this. I'm not convinced the O2 sensor fixed the problem, although I had kind of a poor 70MPH test drive, given a fairly windy test track up in the Rockies. But, in a new development, I was able to get something different on the computer this time...only after I replaced the presumably faulty O2 sensor. Got a coolant temp sensor code (1 long 3 short, I think...not looking at the manual ATM) after the test drive...so I have one of those coming in a bit later this week and will get it swapped out. So, maybe my computer was malfunctioning...I did reset the codes before the test drive, just in case. Further troubleshooting steps taken, just in the interest of putting this behind me. I Seafoamed the intake and crankcase, also cleaned up the fuel injectors again...just to kind of get the engine in top shape. TBI looks fairly clean, and just in case I cleaned my MAF again. Got the fuel filter done, seen worse but it was close enough to time. Oh, and I timed the vehicle here awhile back prior to the road test, spot on 15BTDC and seems to be holding. Did about as good of a vacuum check as I think I can perform..still putting off ripping that EGR valve off there, but will do if the post-code resolution test doesn't go well. Overall, I can tell she's running better doing pretty much a complete 100K maintenance cycle (minus t-belt) at 60K, but that's probably to be expected. I'm really hoping replacing this coolant temp sensor might do something for me. From what I've read about their failures, I haven't seen identical symptoms reported when people have issues with these...but who knows! Appreciate all the advice, think I got most things knocked out from the suggestions so far. I'll report back when I know more! Hope to find some time to take another road trip here next weekend.

Phew. Got that O2 sensor in. I originally mistook the sensor for the exhaust recirculation connected to the headers, mainly because I couldn't see it since the cross member was in the way. What a *%&$...that thing was really in there! Coincidentally, I noticed in my Haynes service manual that the O2 sensor is a regular maintenance item at 60K mile intervals, didn't know that! So, the probable 100K+ miles probably was a bit beyond it's capability and it needed replacement anyway. She did pick up quite a bit it would seem from just that change (haven't adjusted timing yet), but I'll have to make a trip a bit out of town to really test it. Closest good mountain to me where I could reproduce it is a 45 miles west into Idaho. Looks like it's time for a road trip! I tested the EGR valve and it appears to be doing what it should. When I press the diaphram, the engine stutters...returning to "normal" when it's released. I tested it after warmup, too, and similar behavior. I'll get it off and give it a good cleaning, maybe next weekend, after I can get a gasket in. Sometimes finding specialized parts can be a challenge here...checked five stores and nada on the gasket. I've hit a good 90 in mine, not an incredibly uncomon thing here in Montana when you're trying to pass someone going 75.

I haven't been hauling anything when this happens, practically an empty truck with a single passenger. Not big people, by any means either, so we're not talking less than 350lbs total passenger weight. I would call the symptom abnormal...driven this rig over 200K miles through all sorts of mountainous terriain including the Rockies probably a hundred times, so I know her pretty well. I usually have enough power to maintain a good speed up a hill, maybe a little loss but not a what feels like a rapid decline like this does, struggling and completely unable to keep a speed. The problem's happened hot or cold, we get some pretty good winters here and I can recall this issue from some sub-zero trips...so I don't think temps play much. Just checked the timing and it looks like it's off by almost 8-10 degrees BTDC...not sure how that happened (or even how it's running seemingly well otherwise?), but prolly my mechanics jacked it up when they did my valve cover gaskets here awhile back. I checked it sometime after my last timing belt change, so something's obvisously been changed since since that's a pretty good drift. Gonna have to correct that, first, as that could have a lot to do with things. Picked up a new Bosch O2 sensor tonight, gonna give it a go I think since it's obviously probably on it's way out. Couldn't find an EGR gasket and a bit concerned to take it off for a good cleaning without a suitable replacement on hand, so that's gonna have to wait I think. Checked most of the vacuum hoses that I could ID and things look decently OK, no major visual problems anyway...might have to break a hose out and go fishing for leaks to be sure. Anyway, thanks for the idea on checking the timing, it's something I bypassed thinking there wasn't any cause to change it and therefore little reason to think it might be off.

Ah, sorry, that was a typo at $250. Meant $150 as I was looking at the price from the dealership. $40 sounds much better, confirmed on RockAuto at $35 and change. How difficult is it to change out the sensor with Thorleys installed? I remember the last couple times my mechanic complaining it was a bit tough to get done right. (I almost think the headers need to be retapped maybe, like they got galded or something way back when.) I don't see a procedure in the FSM, but it looks fairly straight forward, minus the metal connection, which I'm not 100% sure how it's fastened on there. Is it compression? What? Anything to be aware of or is it just a pull and replace kind of job? (That's mostly the work I do, quick and fast...still not bold enough to take on big projects or one's that require special tools and such as the rig's my daily driver.) Appreciate the insight!

Thanks for the thoughts. I did check the kickdown switch, I hear the click but haven't actually tested the switch for operation. I'm less inclined to think it's a switch issue, since things do downshift properly at lower speeds and sometimes downshifting does work, particularly in lower gears and lower speeds. I checked the old plugs and they were gapped pretty close, around .041 if I remember right when I pulled them. Gapped new ones to .039 to be on the low end and to allow for a bit of expansion. I don't get any rough idle or what appears to be ignition issues, that I can tell. Timing was pretty darn close to 15 BTDC last check, but I suppose it could have slipped in the last year or so. I've got about 50K on my current T-Belt, so doubtful that it slipped...but worth at least checking to be sure. I do occasionally get a bit of knock at lower speeds, so I've been thinking about checking timing anyway and adjusting if necessary. Also, fuel filter was done ~10K miles ago and regularly changed...it's on my list of typical maintenance items to replace this go-round, at least to eliminate something stupid. As for clearing SES's, I haven't been clearing them, so I'll look into that...but my computer hasn't traditionally thrown me trouble. Good call on cleaning up the EGR valve, I'll learn how to do that and put it on the agenda. I wouldn't call myself a good enough self-mechanic to diagnose vacuum lines, but that's one of the things I have on my list for my mechanic to consider after I get done eliminating what I can. I can at least see if they're deteriorating and obviously experiencing an issue...but, nothing I've noticed crawling around recently hot and cold, but also haven't followed them back past what's typically visible from the engine bay just yet. I'll do that. Thanks for the ideas...gives me a few things to knock off between now and next week when I've scheduled another visit with the mechanic. The unfortunate thing is I have to drive almost 90 miles round trip into Idaho to find a suitable mountain to reproduce the problem consistently! Eh, another road trip....

I would also agree that the headers made a noticable difference in both power gain and sound for me. I went to a 2-1/4" exhaust all the way back when I did the upgrade and think that is probably a good sweet spot when you open up over the stock manifolds. Just make sure if you do it that you get the 300ZX manifold bolts as the stock ones are prone to premature failure. There's a bunch of info here on the forums about this, sorry I don't have a part number. You also might consider an oil filter relocation kit along with this, but the default location doesn't throw that much trouble my way with the headers installed...just maybe a bit more inconvenient and usually good to usea burn sleeve when it's really wrenched on there. I'm actually in the process of doing my second cat back on my 260K mile pathy and have opted for a less-agressive muffler this time...100K miles+ on the agressive sound has me seeking something quieter! (Or maybe I'm just getting old, who knows...)

Hey guys, I've got a '95 Pathy SE that's expeirencing an issue I'd like your opinion on. Been experiencing issues at the top end going up hills where I seem to lose a tremendous amount of power. The vehicle will consistently lose speed up a good size hill, going from 75MPH (yay, Montana!) to as low as 55MPH, depending on the size of the hill. Problem doens't seem to be present in lower gears and slower speeds, only in 4th/OD that I can tell, as I haven't had any issues trail running. Problem happens with power switch enabled or disabled, explicit OD on or off. What's odd is that the kickdown/downshift doesn't seem to function properly most of the time when this is happening, but when I can get it to kickdown to a lower gear, the rig still doesn't have the "ooph" to get it up to speed. Also, I think maybe the issue is still present, but far more subtle, at high speed over flat terrain where CC (or manual holding of speed) stuggles to maintain a consistent speed over the terrain. Relevant info...I've been getting O2 sensor SES's for about 8K miles that I've been ignoring due to a relatively infrequent/intermittent nature of them. Those SES's have largely quit in the last few weeks, but it seems to me the timing of this issue has exceeded the start and end of the O2 sensor SES codes. I wouldn't think this could cause an issue this severe, but I've seen a couple people report issues somewhat similar with the O2 sensor. Also, I had my tranny rebuilt approximately 10K miles ago, seems to be in good shape, but wanted to mention it in case it's relevant...but no tranny codes are thrown. I saw another mention of a camshaft sensor in a similar symptom. Seems to me the last time I replaced the O2 sensor was maybe 80-100K miles ago and is my third, including stock. She's also got 260K miles on her, so I fully expect that it could be something fairly uncommon. Recent troubleshooting includes a full tuneup. New wires, plugs, disty cap/rotor, PCV, fulids, etc. Engine is relatively leak free after full front/rear/valve cover gasket replacement. Engine has good power in lower gears, still has the "ooph" at lower speeds . Wheel travel is excellent and likely not related. Oil and coolant look good, no reason to suspect head gasket or anything like that. My mechanic hasn't really addressed the issue over two visits as whatever it is isn't throwing a code, other than that infrequent O2 sensor. I'm thinking O2 sensor, but I don't want to randomly throw $250 at the issue if I don't have to, but I also want to fix the problem. Am I on the right track...can a faulty O2 sensor truly throw these symptoms? Anything else to consider? Thanks guys!

Hi all! So, the other day, I changed out my courtesy lamp on the driver's side. It worked just fine, easy peasy. Well, a day later, I noticed no more courtesy lamp...and all the map lights are out and my clock's gone schizoid. Clock is off entirely when shut down, comes on with key in the ignition but always starts at 1:00, resets with every shut off. There's sure some interesting circuitry here and that clock is weird how it works when the truck is on. (Yet, all lamps don't work, even with truck on.) I tried a second new courtesy lamp replacement, no dice. Tried the original lamp, no dice. I've reseated it multiple times and there doesn't appear to be anything causing a short right there. Now, I'm pretty sure all these lights aren't totally dead, but obviously something else went awry here. It was just a simple lamp replacement, so not sure what could have happened. Before I go checking fuses and circuits, has anyone had anything like this happen? Tips? Ideas? I'm guessing no 'cause I've scoured the web & there's nothing I can find on this. Pathy is a 1995 SE VG30 4x4.

Sounds familiar, but I have the VG30 engine. I recently did my rear main seal, but I was having my tranny rebuilt at the same time...so it was pretty much required. I lived with a leaking rear main for at least a couple years, as others have said, I probably wouldn't recommend the effort to do it unless you're pulling the tranny, motor or transfer case. Just make sure you keep an eye on your oil levels and you're fine, unless you have qualms with leaving small oil puddles everywhere. Then again, you could just swap motors...but that seems like a big hammer for a small problem. As for the timing chain cover, it's probably the front oil seal and probably due to mis-installation. It's not a terrible job, but there's a lot you have to remove to get to it and it will take time. (It's usually quoted around $800-$1K, almost entirely labor.) It's always a good idea to replace the water pump, t-stat, and lower coolant hoses (and anything else that's remotely worn) at the same time while you're in there, even if they've been replaced previously, because they're cheap parts and expensive/time consuming to fix later. I always have my oil seals replaced as well. There's a few guides out there on Youtube, defnitely recommend checking them out.

Transmission received...

You're gonna have a hard time finding headers for your '97. From what I understand...Stillen used to make headers but they are no longer manufactured. Nonetheless, replacing the cat, muffler, & pipe to 2.25" or 2.5" will make a difference - albeit not as much as if you could open the flow up from the intake all the way back. Duals could create a situation where there is not enough back pressure and you will actually lose power in your bottom end. I have heard the same about the Tornado...you can read a review from someone who did actual HP/MPG tests on the product here.

That sux! Guess I'm glad I'm down in "balmy" North Carolina for this cold spell we've had back in Spokane! Back there Tuesday, though...wondered if my truck will start right off the bat. It's prolly the battery as they use more amperage in cold weather conditions than in warmer. This causes additional strain on the battery by needing to produce more amperage - an older battery can just not be up to snuff for these conditions. In fact, this is where we get the term "cold cranking amps" as a battery is measured by it's amperage performance at 0 degrees celcius.

Nice golf cart! It's scary to think that in 20 years, this "concept" could be kewl. I remember seeing the concept cars in the late 80's/early 90's...we're not too far from those concepts now.

Schweeett, CaseyT! That's awesome! When do they arrive? Yeah...the $1250 was a bit hard to choke down. It went down better after a few brews, though! It's a pretty amazing difference with the new exhaust and all...it's hard to say if it's worth the price. After it all sinks in for awhile, I'll be able to tell you if I'd do it again. EDIT: CaseyT...I found out that the tubes that are slightly extended from the flange is perfectly normal and found on most sets of headers. This insures a solid connection from the engine to the header and is best sealed with a gasket sealant compound of somesort applied to both sides of the gasket. No need to deck the flange.

Wow...that's pretty remarkable. I honestly can't believe there was that little damage from that high speed of a crash. I'm with the others that say major bodily damage would have been suffered...certainly more to the driver than the passenger. In the real world, this vehicle may have fared better if it hit another car instead of a brick wall. Let's see head on collisions of two smart cars!

Yeah...I'm seriously thinking some type of open air intake will be the way to go. I get this little "whistle" sound from the current intake...it's wanting to pull a bit more air than than the stock setup can handle. I think the JWT's are no longer made...correct me if I'm wrong. I know AC has a couple choices...or I could make my own from a K&N filter, although a kit is most desireable for durability sake. Any ideas? The pix are up: Pix Of Header & Install (See Installation Section)

I think a faster way than going south through dri-sh!$$ies would be to take Hwy. 2 through Stevens pass. It'll put you north o' Seattle...but doesn't look like nearly as much a detour as going down to Hwy. 14 or 84. Sitting in traffic in snow sux cause your chance to wreck by somebody doing something stupid is pretty high. I once sat for 12 hours coming over the blue mountains on Hwy 84 from Boise...miserable...by the time I made it to Pendleton, I was so exhausted I had to plunk down $60 for a hotel as I could go no further.

Oh, I fogot to mention...if you plan on justifying this upgrade based on gas mileage savings...forget about it. If I saw an improvement in highway mileage...it could be measured in micrometers on the gas guage. I know this because it takes me EXACTLY 3/4 tank to go from Ritzville, WA to The Dalles, OR. Maybe 1 MPG increase...not significant enough to pay off the investment within a couple years. Ah well...at least it sounds kewl.

Monroe also makes an OEM style SS that will fit with the OEM Nissan bracket. It's what I have and it does a pretty good job. I notice it most when traveling somewhat fast over rough roads - my body shakes all over the place, but my steering wheel doesn't jerk back & forth. It also keeps the truck from lurching in either direction when it's travelling over bumps. If you don't have one, I think it's a great upgrade for the price. ($75 or so, installed) Don't know that it would fix your problem, though. Sounds like your problem doesn't appear to be caused by terrain...and the tapping the brakes thing has me a little perplexed.

So, I was down in Portland for the holidays and I decided to run out an see if this exhaust place I used to go to would be interested in doing my header & exhaust install. The place is called Exhaust Specialties/Master Muffler and they're well known for doing great work. After some discussion and a "guarantee" it could be done by Saturday afternoon at the latest, a deal was struck by 10AM Friday morning. Work to be done: Old exhaust out, manifolds out, headers installed, new cat, new muffler, new tail pipe, new O2 sensor installed, and any other "stuff" that pops up. Work commenced immediately. Yeaaaaa...I was gonna have headers and new exhaust! DAY 1: Work began by ripping out all the old exhaust. Sparks are flying, pieces are dropping...this has got to be an exhaust guy's favorite part of a job like this. A few torques of the down pipe & Y pipe...and we're clear to start work on the manifolds. On to the passenger side manifold - which had the famous ticking sound pretty bad. Heat shields off, wheel was off, inner fender wall pulled back & the studs were coming out remarkably well. All of sudden.... :o ...one of the manifold studs broke off. No matter...Don steps in...welds a nut & washer to the stud...and ziiiip...comes right out. Great. New studs are placed...gaskets are prepped with liquid copper...and about 4 hours after beginning, I have a passenger side header. Purty. On to the drivers side. Same preparation takes place...time to take the studs out...damn...two break off. Another two washers...two nuts...quick weld...and BAM...they're out. Whew...a wave of relief...I won't be here until next week. Sink some new studs...gasket prep...and the drivers side is on. Really purty. After looking at the air tube that connects to the drivers side header, it's determined some fab work will be needed to get it to fit right. That's why I like these guys...it's not just that it works...it's that the job is done right. It's about 5PM & it's decided there's no way things will be done today. DAY 2: The day begins early...7AM...an hour before they open. My throttle body is taken apart, air tube is pulled out...and we enter into a 2 hour bending/fitting back and forth marathon. Finally the air tube fits without forcing it...and my throttle body is reassembled. Ah...finally...the PITA is done and we're on to the fun part! -bounce- Side track: Another Nissan WD21 truck pulls in to fix a manifold stud that had broken off. Poor SOB...after much work...it's determined he's gotta pay $500 for a new manifold install. Bet he wish he had headers lined up! After insuring a fit for the down-pipe and Y-pipe, the gaskets are prepped and everything comes together. Perfect fit on an auto tranny with no mods to the Y or down pipe whatsoever. Fabrication begins on the pipe that will lead into my new hi-flow cat. A mount is welded so I can have a disconnect at the Y-pipe and the bung hole is prepped. A couple hours later & were ready to mount it. Yippee! Next, the new Eastern Catalytic hi-flow cat goes on without a hitch and the OBDII air tube hold is cut & welded shut. The new Magnaflow XL muffler is pulled from the box... ...it's freakin' humongous (and purty!!!). The installer is thinking :furious: and fitting is done to get the connector from the cat to muffler (about 3" space) to fit right. It's a PITA...the installer seriously jokes that this is way too pretty of a muffler to put on my truck. No matter...it's soon on and finally to the tail pipe. The end is near! The tail pipe is deftly bent and soon welded on. Custom exhaust hangers are manufactured and welded to the pipe. The O2 sensor wires are spliced and it is installed into the new bung. The Y-pipe is welded to the down pipe. Oooohh...time to fire it up! I step in to the truck...fire it up...and VROOOM...she comes alive with a deep rumble! Some quick bursts of throttle & she roars pretty good! Everything is checked for leaks and all is clear. It's about 4PM and it took 15 hours but they got it all done as promised. So I'm off rumbling down the road...happy as a clam...and then I get to the freeway onramp. Back off from traffic a bit and I let her rip down the on ramp...OMG...she sounds wicked! All that air moving up front just makes this wild sound. Oooooohhh...super happy. Worth every :furious: penny paid! (About $1250 w/ headers, exhaust, cat, muffler, install) So...I'm all excited...get my GF and head back to Spokane. Any time I get something done to my truck...I always ask the GF if she notices a difference. "No, sorry honey." is usually the answer...and is again the case here. We're rumbling around and finally get to the onramp for the freeway. I decide that there's NO WAY she could not notice this one...so I let her rip up the freeway onramp again...and the GF's like, "OK...I hear a difference. It sounds like a racecar!" Yippeee...sorry to drone on...but thought you would want to see the write up. Pix of the install will soon follow in the pix & vids section later this evening!

Hmmm...not totally opposed to going west...but with the main pass down to one lane these days due to the rockslides...it could be a significant wait if the weather up there's crummy. -thnkboutit- I'm off to North Carolina for a couple weeks as of next week. Maybe first of the year or thereabouts would be a good time?

Yeah, I've got my Thorleys ready to install too...just need to wait until after the holidays. Not enough time! My flanges aren't flat either...it struck me a bit odd. I've been thinking about getting' em decked flat...but I imagine that with the gaskets, you'd probably be all right. Not sure if my exhaust guy will do the decking...but CasetT did mention there's a NAPA here in town that has a decking machine. You might check around in your area to see what's available. Let me know what you decide to do!

Hmmmm...blue smoke is usually not a good sign. It's almost always caused by oil mixing with gasoline in the cylinder and being burned off with the fuel. You're on the right track with the head gasket. I would also consider cam seals just in case you're seeing two problems - such as minor piston blow-by and a separate leak. You will be able to see that by pulling off the rear TB cover...which it sounds like you may have to do anyway. Either way, your situation doesn't look great. Have you checked your plugs lately? (Oil) How's the vehicle running? (Smooth/Rough) Has the truck lost it's power at all? From my experience, once you see blue smoke...it's a rapid downward spiral into engine rebuild time.

I got a pic of the car wash guy's expression...it wasn't all I had hoped for...but man...the guy looked purty funny when he was walking up. Got a pic of that, too. Check out my site. I wouldn't mind headin' up north a bit with you guys. There's lots to do & see up there. It'd be kewl to do a quick run up there someday. CaseyT was sayin' something about some neat sound trails he found.