johnm

Hi guys, I have sort of a weird problem. I have 99, SE, 4x4, a/t that gives intermittent DTC/SEL/Check Engine light with codes P0131 and P0151 (Bank 1 and 2, front O2 sensor voltage low). I say intermittent because it will come on and then go off by itself. The truck has 140000 miles, so I initially thought the O2 sensors were going bad, so I replaced them. Still getting the codes. The freeze data (which I've looked at a few times) shows that the codes get thrown at high engine loads, 50-80% load, MAP>60 KPA. If I drive "gently" for a couple days, the light goes off again. I don't know why engine load would have an effect on the O2 sensors. An intake manifold leak maybe? I did have the intake manifold gasket replaced a couple months ago to fix a coolant leak, that's about the time this problem started. I've checked the O2 TSB for the voltage between the intake manifold and the block...well within tolerance (typically I get 6 millivolts, the tolerance on the TSB is 20 mV). Still I cleaned the wiring harness grounding points on the manifold, just on general principle. The engine sensor monitors on the scan tool all read "OK". The service manual says the code indicates that the O2 sensors are not reaching the maximum voltage the PCM looks for. OR that the voltage is consistently below 200 mV. Given that the codes will "self clear", I expect it's the former, rather than the latter reason. Any thoughts or suggestions would be appreciated. I'm pretty much out of ideas on what it could be, but thought I would ask before I took it to the mechanic.

Yes, only on bumps. I can only tell you what mine did. The threaded end of the strut rod had gone completely through the mount plate, so the top nut was about 1/2" above the mount plate. Every time I went over a dip or bump, the strut would extend and the clunk was the nut hitting the mount. It was easy enough to spot, you should be able to see the mount, strut rod and nut under the hood. I'd post an image of what it SHOULD look like, but I can't figure out how to do it.

when my R50 was making a similar noise, it was a broken upper strut mount.

yep, you gotta pop the lower interior trim panel. With the door up, if you pop the snapped along the bottom the panel will bend enough to let you reach up and change the bulbs. I would recommend getting an inexpensive trim tool from Harbor Freight Tools or the $1 bin at AutoZone or something, makes the snaps a lot easier to deal with. Oh and if you are replacing one, do both, so you don't have to open it up repeatedly.

According to that link, they are towing 1000 lb over the rated vehicle load and have oversize tires. In other words, major stupidity. It's no surprise they think the OEM brakes are not good enough, since they were engineered to match a given tire size and vehicle gross weight. Also, notice that they didn't post any actual braking data (i.e. distance to stop) ...they only say the brakes make them feel "more confident." I'm sort of getting the feeling that you just want to have drilled and/or slotted rotors?

Diminish useful life? That's kind of a hard answer to define. Performance parts, whether it brake rotors or something else, generally have less useful life, the trade off is higher performance. But like I said, unless you are doing a LOT of heavy breaking, the added performance isn't going to be noticeable to the everyday use. I would suspect that new rotors, pads, drums and shoes, along with a good fluid flush should renew your braking system quite adequately. Oh, I forgot, stainless steel brake lines are meant to eliminate the slight (read: barely noticeable) loss of braking performance from regular brake lines. When I was autocrossing, I replaced the ones on my car...the only difference it made was a slight difference in the feel of the pedal...I didn't notice any difference in performance.

Drilled and/or slotted rotors can not be turned. Drilled rotors serve 2 purposed. Increased cooling, and lighter rotating mass. Unless you are doing some SERIOUS braking that you routinely encounter brake fade, you don't need them. Slotted rotors are intended to keep the pad surfaces from getting glazed (which reduces braking capability). Glazing happens when pads are overheated. Unless you are overheating your brakes you don't need slotted rotors.

It is a little weird, it almost has to be something specific to the #1 cylinder, right? The #2 O2 sensors don't affect fuel mixture for the ECU, that and the MAF, EGR, and other things that serve more than 1 cylinder would give you something other that just what you got. Fuel injector for #1 might be bad? Valve spring going bad so not getting compression every time? Piston rings? But would either of those only show up on warm restarts only?

I would suspect the rating difference between auto (5000lb) and manual (3500lb) is due to the gearing of transmission. I could have used a writeup for a 7 pin last summer, but I already installed it. So, you're not the only one.

Thanks XPLOR, for the fast reply. I should be able to do the control arms if I leave the ball joints in place. I'll check out the bushings at 4x4parts.

Hey all. I have a little bit of a wiggle in my front suspension, not bad but noticeable. Anyway, the pathy has 128000 miles on it, and I believe the problem to be the driver's side, lower control arm, rear bushing. I don't seem to be able to find just bushings for it, so that means replacing the whole control arm. Here's my dilemma: The service manual says to replace the control arm you have to disconnect the front drive axle. To do that, you have to take the cap and parts off the end of the drive shaft on the outside of the hub. So here's my questions: 1) I'm not sure I can do this myself. Has anyone done this and where does it score on a 1-5 wrench skill scale? (I do have access to the base auto hobby shop so have a lift and special tools and things, so i wouldn't be doing it in the driveway. 2) If I'm replacing the control arm, should I do the ball joint at the same time? 3) Should I do both sides at the same time?

Personally, I chalk it up to drive train drag.

yes, the ac clutch is working.

Follow up/more information. The pathy is doing this following a throttlebody/intake cleaning treatment. I realized the other times it has done this is after replacement of parts (the first time the distributor, the 2nd the spark plugs). It's not generating any SES codes. After doing some reading of the service manuals and the interwebs, the only thing I can reasonably guess is that the ECU "learned" settings are causing the high idle. Since there doesn't seem to be an easy way to reset the ECU to the factory default (other than with a diagnostics comp), I guess I'll have to live with it until the computer relearns.

My 99 is doing something that's a little weird, and I'm wondering if you guys have had similar experience so maybe can help me out. With the AC on, the idle in Park is 900, then after I speed up and slow down, it gets a little higher every time, like there something sticking. With the AC off, it's around 700-800 and seems to drive and act normally. I know the idle is supposed to go up slightly with the AC on, but not that much right? It did this for a while when I first got it, and then stopped doing it for a couple months, then it did it for a week and then stopped and now doing it again. Anyway, I'm wondering if the cable actuator over on the right side of the engine bay is sticking or getting a bad signal or something? Any thoughts would be appreciated.

Just to follow up. The correct name for the part is the Thermo-Element. Dealer only part, $150. I changed it out tonight after work. There is an o-ring around the element, I guess it tends to leak after a while, the parts guy said it's not uncommon.

Hey all, I tried searching and found some related stuff for pre-96 models but nothing specific enough to answer my question. I have had a coolant leak for a while and finally found it. It appears to be dripping from the gasket at the thermo-element on the throttle body. I'm wondering a couple things: 1) Can I replace that gasket without removing the throttle body from the manifold? 2) Do you think I should just replace the whole thing since the pathy is a 99 with 120K miles? Edit: OK, I can't figure out how to put images in posts, so here's a link http://server6.theimagehosting.com/image.php?img=pic1.b41.JPG&album=0&public_view=1 Update: Spent half the afternoon search for parts. It looks like (at least online) the only way to fix this is to replace the whole throttle body. I'll see what the dealer parts department says on the phone tomorrow.

HA, if only mechanics were that honest. Which is why I like to do my own work, at least then I know it's done right. But my job doesn't afford me the time to do the work myself anymore. It does pay the money to have it done though, so I shouldn't complain too much. And you're right, at least it's fixed before an accident.

So yeah, it's helpful if the correct struts and strut mounts are installed in the first place. UGH, sometimes buying used cars sux. Edit: OK so it's a couple hours later and I'm less mad. This is the story. When I bought the pathy, they put new struts in it. But apparently didn't put new strut mounts in. The front pass. side mount was busted, so I had them both replaced. When I turned in the truck at the shop this morning, I asked them to check and make sure the struts were the right parts for that model/year. The front drivers side was the wrong strut. When I looked a the strut mounts they installed (nissan OEM ones) they were different than the ones that had been there, so I'm guessing the wrong strut mounts were on it in the first place. Obviously I don't know for sure what the old mounts were or why they were on the truck in the first place. If I cared enough I would have asked for the part numbers and looked it up, but some things you just gotta let go, ya know? It just makes me mad when stuff is done half-assed.

No, there is an inch of space between the nut (threaded on as far as it will go) and the strut mount. Yea, I gotta get it looked at ASAP.

So about 7-10 days ago, I started hearing a squeak sound from the front passenger side of my pathy. I knew the front bearings were worn, so I figured that was it. I had them replaced yesterday, but still have the squeak and hit a pothole on the way home and heard a loud thump from the suspension. I went to look at it this afternoon. I was thinking I'd check the strut mount bolts first (why not start at the top, right?). First thing I see is that the strut rod nut is loose and not tight against the upper strut mount. Not only is it loose but the threads on the strut rod end like 1" above the strut mount. The strut mount isn't cracked or deformed. It's like the strut rod lifted up, or pushed through the strut mount bearing. Is that even possible, that the mount bearing broke? Or did the shop put in the wrong strut? Any ideas or help would be appreciated.

1) Make sure you get the correct length wires. 2) Tie a string on the end of the wire when you pull it down (or up) between the engine and firewall. Then tie the new O2 sensor wire to the string and pull it back down. Makes getting the wire routed correctly easier. 3) The drivers side wire is really difficult to get unfastened from the factory tie locations. Be patient, expect some scratches. 4) Zip ties are your friend, when you re secure the wires, make sure they are away from the exhaust pipes. 5) The drivers side O2 sensor is covered by a heat shield extension which you will have to bend out of the way unless you have an offset drive box wrench or O2 socket. 6) Unless they are really rusted into place, once you break them loose they will probably unscrew by hand. 7) Unplug and pull out the wires FIRST before unscrewing, screw the new ones in THEN route the wires, so you aren't fighting with the wiring harness twisting. 8) Don't forget the anti-seize when you put the new ones in. That's all I can think of from doing my 99...some of these may not apply.

A lever next to the transmission lever on the center console.

See this is why I think I was confused, were 99 models built with both 14a and 10x transfer cases? And how do I tell which is in my truck?

Hey all, I just need to verify some drive train info before I get to changing fluids. for my 99 SE 4x4 it should be: Front diff is open, gets API GL-5 80W-90 Trans is automatic, Nissan Matic "D" or Dextron III Transfer gets Nissan Matic "D"? (or does it get 75W-90 API GL-4) Rear diff is LSD, get LSD GL-5 80W-90 Oil? (on other LSD equipped cars I've had this means it has friction modifiers in the oil, which can also be added separately) I've looked at the service manuals I have and it's not really clear to me so, I'm asking for a little help.