I have had my 14" Air Cleaner on for about 3-4 months now and in the winter it was fine. Now that the summer is here, I get this BIG time hesitation, and it seems more evident when the car is hot. What could this be? I have also noticed that when I start up the car sometimes it just goes to 500 rpms then stalls unless you give it gas. I can hear the fuel pump working like it is sucking in air when this happens. Also the other day I was driving it and the rpms started bouncing from 800 to 250 then my car just stalled. I have already added fuel injector cleaner, could this be an O2 sensor? Any ideas? Thanks,

 

it got 95 degrees here one day and it was very humid and i didnt see hesitation or problems with my open element

 

try the fuel filter take it out and blow through it to see if its clogged

 

maybe you're just running lean? does the engine shake? does the tack fluctuate between rpm's? what else have u dont to the motor? anything internally?

 

timing maybe ... i noticed i had to do timing to compesate for the winter weather a few months ago.
~Tim

 

I changed the fuel filter about 2 months ago. I don't know what it could be. It idles at 500 rpms and sometimes it just drops and stalls out. Could this be a bad fuel pump? I also have notced when I am driving I press the gas and there's a 2-3 second hesitation which I think is related. Any help is appreciated.

 

if you are startign the car codl and the rpm's ar only going up to 500 then your most likely culpriut is teh IAC. when they die teh car will be screwed up off idle, bad warm up loop, and the rpms will usually drop really low if you just jump off the gas quickly.

later
tim

 

This is probably a dumb question, but what does the IAC do? And how do I replace it? This morning when I was at a stoplight after driving the car for about 5 minutes, it wanted to stall. And sometimes when I start it up, it doesn't have enough rpm's so it just dies. Is this IAC related?

 

i dont think this is iac realated because as soon as u start the car it will die if it was the iac... it stands for idle air control valve. all this does is let air into the engine at idle when the throttle plates are closed so that the car does not turn off. vacuum "sucks" the air into the engine to keep it running.

 

definetly vacuum leak.
Make sure all of the vacuum lines are plugged up.
I believe the culprit is on the front left of the tbu unit
stick a screw in there with rubber hose around to seal the leak