Start and stall, doesn't idle

[cruiser69]

I have a 02 GT 3.8L with 85k on it. Right now the car has a hard time starting. If it is cold it starts up fine. When it warms up it tries to start and dies right away unless I give it gas to keep running. Sometimes the tach will go from 1000 to 0 and bounce up and down until it dies or barely keeps running. It is hard to keep it running at a stoplight sometimes, but then other times it runs just fine without any problems. I have cleaned the MAF sensor and the IAC valve and it has a new fuel filter on it. The IAC was really black when I cleaned it. Could this be bad and need replaced. The MAF sensor was replaced 9 months ago and the condition does not change when it is unplugged. What else should I look for?

[olopezm]

You should check for any vacuum leaks around the engine. Should there be any major leak, it can cause the engine to keep stalling and the RPM's going up and down. You can remove the IAC and see if it moves when you turn the key to the start position.

Or if you could borrow it from someone else it would be a great way to know if yours is either good or bad.

Best regards,

Oscar.

[tblake]

If this were a 97-00 GTP I'd suggest the fuel pump resistor. But your car doesn't have one. When it stalls out, does the "trac off" light come on by chance?

[cruiser69]

The trac off light does not come on when it stalls out. I did get the P0172 error code twice but that has been a while and it has not come on again.

[richtazz]

P0172-system too rich. This code could mean a myriad of things, so for this issue, it's virtually usless.

I would try unplugging the MAF sensor with the key off, then restart and see if the car quits stalling. This is a common symptom of a failed MAF and it won't necessarily trip a trouble code.

[cruiser69]

I put a new MAF in about 9 months ago. Could this be bad already? I noticed that the car will die when put into park sometimes or if you have the fan on and turn it off the car dies also. Would a bad MAF cause these issues?

[richtazz]

if you purchased a reman unit from Cardone, there is a very good chance it could already be bad as they are terrible. Any change in load on the engine can cause a stall when the MAF is bad, whether a physical load (putting the car in park) or a change in electrical load (as the alternator draws more power the more amps it's producing).

[cruiser69]

I borrowed a MAF sensor from a friend that has the same car as me. Hooking up the new MAF did not change how it is running. Only thing I noticed is that the car does not die when put in park if MAF is unplugged. That is the case with using both sensors. What other things could cause this problem?

[cruiser69]

I was wondering if my fuel pressure regulator is bad. I pulled off my hose to the regulator and turned the key to on and gas came out of the hose. Someone told me that usually means the regulator is bad. Let me know if I am on the right track.

[olopezm]

That's correct, the hose should be free of any fluids, in your case the diaphragm inside the FPR is broken thus leaking fuel.

Best regards,

Oscar.

[tblake]

Funny I was just going to suggest checking the FPR this way, but looks like your one step ahead of me. Good luck.

[richtazz]

I agree you have a bad FPR, any fuel coming from the vacuum port would indicate it has a torn diaphram.

[cruiser69]

Put in a new FPR and the car is running good again. Thanks to everyone for the help.

[richtazz]

thanks for the follow up report, we like happy endings!