Hoping (PRAYING!) this sounds familiar

[TAC]

I still have my "fuel starvation" problem. I have another clue that may add some insight. The symptoms are that at a certain point in time, the car refuses to accelerate properly. It acts like it's out of gas. The symptom occurs in boost and not in boost. The first time it showed up this time I simply pulled away from a stoplight going around a left turn. The engine hesitated for a brief second and then continued. I was not "getting on it" and it happened when I shifted to second and continued to accelerate at a very moderate pace.

I immediately went back on the highway and started testing. If I punch it, I get the bucking. If I accelerate a little slower, I get sputtering and hesitation. This all took place with the tank showing 2 bars below 1/2. I went to a Chevron and filled up. It took 12 gallons...about what it should be. The tank appears dead on capacity wise. The problem continued with a full tank...no real difference. The boost guage never gets above 50" cause I shut it down as soon as I notice the problem and the problem shows up well before the turbos get completely spooled up.

The new clue is that the problem appears to be heat/time related. Very similar to old vapor lock problems. I recently replaced the fuel pump hoping that would fix it. I never saw the problem again because I never drove it for that long of a time period. This time I had been driving on the highway for 2-3 hours before the problem showed up. I let the car sit for 3 hours and went back out and the problem was still there. I let the car sit for 24 hours and went back out and no problem whatsoever. I can rip through the gears with impunity. I drove and tested for 1/2 hour tonight and could not get the symptoms again. The boost guage looks very steady and pegs at 52" while floored when not exhibiting the above symptoms.

I am really hoping this rings a bell with someone. I can think of lots of things such as:

vapor lock?
pressure in the gas tank?
ignition problem-component failing at high temps?

All suggestions are appreciated. I hate taking this to the shop without a good idea of what's wrong but I don't have much choice. It appears something is failing when hot. Please help.

1 issue that I don't think is related but I'll toss it in. My throttle is sticking slightly...the revs stay up when I shift. Kind of like a stuck choke-a very light tap on the gas pedal always drops it back down. This happened once before last year and a very thorough spraying of the linkage and spring with carb cleaner eliminated the problem and it appears I've eliminated it again for the time being. With the engine off the spring seems very solid and returns the linkage to the stop with no hesitation so I don't know why it sticks with the engine running. Is my cure the accepted method for this or am I masking something like a bad throttle position sensor or ???? Could this be related to the above issue?

Thanks for all help.

 

[billd]

similiar problem

I had a similiar sounding problem in a firebird a couple of years ago. When it was hot the cars would just quit (sometimes). I took it into 2 mechanics and a pontiac dealer. (and of course the problem would never manifest itself while they had it)

After the Pontiac dealer looked at it and told they could find nothing wrong I picked up the car on the way home it quit running I had it towed back to the dealer and this time they fixed it. (keep in mind this took place for teo years and never occured in the winter)

It turned out their was a piece of insulation missing in the windings of the fuel pump and when it got hot the windings would short and the pump would stop until it cooled off then it was fine. I put in a new pump and relay and never saw the problem again.