Ok this is starting to get annoying...

The problem only happens when the engine is warm. These are the symptoms:

Bucking and hesitation, intermittant backfire, under load.
Only in 2nd and up gears (not 1st).

So far, new plugs, wires, coils, ICM, EGR, TPS, IAT, Air Filter, Fuel Filter.

Fuel pressure is 43-45 when not running and key on, 35 psi running which is to specs. I've driven it and watched the fuel pressure and it doesnt dip or anything when the problem occurs.

However last night I noticed that I had 22 degrees of advance at idle. This is way off. It should be 12-13 degrees at idle.

What would cause this? Cam position sensor? Crank position sensor? Remember no codes and very intermittant problem when engine warm (hardest to solve ) Let me know what you think.

Thanks for your help

 

I can't see how anyone could provide a good answer to this, since you haven't bothered to mention the year, model, engine, etc. Tell us what engine it is, and I'll move it to the correct Engine Tech forum for you.

Generally a good idea to set up a "signature" with basic info about your car - year, engine, tranny, major mods, etc. - so people have enough info to answer the question.

 

I had an 89 doing the EXACT same thing, tryed for weeks (not a constant everyday but when we had time) needless to say we sold it and still had no idea what was wrong.

 

Sorry:

95 Camaro 3.4L

The reason I put it in this forum is because I was looking for someone with advanced diagnostic skills.

Nobody in the engine tech forum has been able to help me out thus far.

I'm pretty sure its narrowed down to the aforementioned sensors or the PCM.

Does anybody have any leads on this or offer some direction to go.

I have very good mechanical skills to test and diagnose as I was an automotive technician at a GM Goodwrench Dealership for 3 years.

Thanks again

 

Perhaps this problem is to complex for this forum and I should seek help elsewhere.

 

run a compression test if you haven't already. if everything is running good there, you've ruled that out.

 

With an attitude like that, no one will miss you.

 

What rock do these guys crawl out from under?

A PM from "simzjr":