BowTied

Neat project. I really suggest doing a before and after dyno. The "butt-dyno" can be mis-leading - you can feel like you gained something in one spot but overall have a net loss. There must be dynos near you, call the guys at Legendary Motor Cars they should know who has one nearby. There is one in London right near the airport (Chandler). If you want a simple baseline run or two to establish what you have (no tuning) I'd think it would be well less than $100. There is also a guy in Woodstock that is into building perforamnce Mustangs and other Fords but I didn't really like the guy (he did the dyno for my Chevelle) but he did have an impressive set-up. Mike, I am inclined to agree with the comments about 2.25 being on the large side. It is over twice as large (2.25 times actually) as 1.5" pipes. Even if the OE pipes are 1.75", that is still 1.65 times larger - I think that is significant - particularily as you say you are looking to build torque not HPs. The best bet to build torque is the long tube header that is designed for the engine in question as it will 'tune' the exhaust for best scavenging. The pipe size afterward is also important. Although this is a completely different animal, I think it illustrates my point: My Chevelle made 10HP more with open headers - but lost 12ft.lbs. For me, that didn't really matter as I started out with over 400ft.lbs, but I think opening the pipes up that much will have a similar effect. If the original pipe is 1.5 going to 1.75, or orginal 1.75 going to 2 - those are approx 1/3 larger and may get you what you need and be easier to bend and tuck up in the body. I am not an expert by any means. If your research shows otherwise, cool, I am intersted to hear about it.

I don't own an X but there are LOTS of guys wheeling with them quite successfully. They have a 3.3L engine so I can't see them being that much different for towing capacity than a WD21 or what am I missing there? It may depend on what you are towing, as with most vehicles, a manual transmission derates the towing capacity. They also have a super charger option if you wanted more power.

Kingman is correct. It has to do with exhaust gas velocities. There are a couple ways to look at things for a n/a engine. Design the exhaust for bottem end or top end. "Smaller" tubing forces the exhaust to move faster through the pipe. The beneficial effect here is the scavenging effect. "Larger" pipes tend to lose this and in comparison can make acceleration from a stop feel sluggish if the pipes are too big. The trade off is the larger pipes with breathe easier at higher RPM. Case in point, when I dyno my 6.6L V8 it gained 10hp with open headers, but lost about 12 ft.lbs of torque. For heavy vehicles, especially trucks and off-road rigs that are running at lower RPM, it is all about the torque to get it moving. The extra few horsepower at the top end will not be worth the loss of low end grunt. IMHO.

you were so close!!! I can understand your frustration though.

Was this sudden or getting worse over time? What does your temp gauge show? If it stays low even after a while, the stat may be stuck open. This means the truck would take a long time to warm up and use way more gas. Original O2 sensors? They could need replacing... There are lots possibilities here. Can you give more info?

Could be an exhaust heat shield that has a rusted mount and is vibrating.

Thanks for comment... The 3.5L VQ pathy power valve screw problem, as I am told, applies to automatic transmissions only, 5 speed transmission do not have this power valve system. If the manual trans rigs have swirl valves or not, I am not sure. The write up... http://npora.ipbhost.com//index.php?s=&amp...st&p=277553 There is or was a recall for Sentra's that had the same problem. Nissan won't help pathy owners unless you have a failure under waranty. Note failure often means catastrophic engine failure here. Don't wait on this. I don't think it is stickied? So I thought it was would help the OP to not have to search for it.

some causes bad fuel / too low octane for application timing too far advanced heavy carbon deposits running lean I was wondering about the last one, re: vacuum leak?

Need more info on this ground wire not connected??? Bad or missing grounds can cause all kinds of problems, especially erratic things. Verify all your ground connections touched during the B/L. I say hold off on the second can of cleaner for now, unless things were stupid before a second can would be a marginal help if any. After the fuel filter change try it again. If no change, look for a fuel line or hose that has been pinched, bent etc. If fuel is being restricted it could idle fine but cut out at higher rpms, especially in higher gears.

This wouldn't explain the fuel smell, but winter formulation fuel may reduce your fuel economy.

Well just put a resistor on the O2 sensor too!! And this explains some bad feedback for the seller I think.

I think you have some good advice so far. I through out an oddball, that you may want to check when getting the balancing done just to be sure - a bent rim can be hard to notice depending on how it is bent. If the tire tech put it on the balance machine and closed the hood, he would never have seen this. I have a similar vibration on my old Chevelle I have traced to a bent rim. Long shot, but somethign to keep in the back of your mind. You may find swapping fronts to rear will help troubleshoot to see if the vibration moves to the rear or not.

yeah, sounds like the sending unit wire is grounding out somewhere.... ?

^ What he said. I suggest having the fans come on just slightly above the temp of the tstat. That way they won't run all the time, just when needed (like in town). JMO

Assuming all connections at the starter and battery.... Starter relay/solenoid? I am not real familiar with those rigs tho.

Be sure to NOT use the caulking that is bathroom tub & tile or any that has that vinegar smell.

Turn the key off then on at least twice without starting, then start. Do this for a couple of days at least. If no issue starting, then it could be fuel pump/regulator not building quite enough pressure...

I agree. Leaky axle seal. The wheel cylinder would have been easier to deal with I think, sorry.

As the saying goes: "Good judgement comes from Experience. Experience comes from bad judgement." Keep on working away at it, every job we learn something for the next time...

Mine does it too. Spraying it helps, but the spray collects dirt. I use a bit of spray silicone on a rag and wipe it on, seems to help.

Perhaps the distributor should be pulled out for inspection - if the gear (or the pin theat holds it on) are wrecked - you could be doing other damage.

Lots of engines have head bolts that go into water jackets and require sealant, IIRC, permatex#2. Could you tap this 1/16" hole such that a tiny set screw with some sealant on it could get in there with a long hex key? Even if the answer is a set screw can't be done.... If it were mine, I would make CLEAN, like kick ass eat off of it clean, and JB it and then put some sealant on the threads of the bolt (use a NEW bolt). My bet is it'd last 50k miles + Good luck

If it doesn't get higher, likely fine.

Glad you got that sorted out. Keep an eye on things, you may need another flush....