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Tool Hut
Tool Hut, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 494
Experience:  Owner of a mobile diagnostics company assisting auto technicians with difficult vehicles
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2002 Grand Am 3.4 idle drops and then car stalls

Customer Question

2002 Grand Am 3.4 idle drops and then car stalls
Submitted: 11 months ago.
Category: Pontiac
Expert:  Amedee replied 11 months ago.

Hello and welcome! My name is ***** ***** I can assist you with your question. Have you checked the fuel pressure regulator?

Expert:  Amedee replied 11 months ago.

Check to see if the fuel pressure regulator is leaking. If so, the diaphram has ruptured and will need to be replaced.

Expert:  Amedee replied 11 months ago.

Another possible cause would be an air or a vacuum leak or possibly a bad MAP/MAF sensor as they both can cause a stalling condition.

Customer: replied 11 months ago.
It is good. Dry and holds vacuum
Expert:  Amedee replied 11 months ago.

Excellent!!

Customer: replied 11 months ago.
No vacuum leaks. How can I test the MAF or MAP sensor?
Expert:  Amedee replied 11 months ago.

You can use a voltmeter or a scanner

Customer: replied 11 months ago.
What are the specs
Customer: replied 11 months ago.
We have a snap on modus scanner
Expert:  Amedee replied 11 months ago.

Perfect!

Expert:  Amedee replied 11 months ago.

Watch the readings at idle and see if they drop down before the engine stalls. If so, the sensor is bad.

Customer: replied 11 months ago.
Waiting for it to stall. Right now the MAF sensor is between 4.23 and 4.42 Volts. MAP Sensor is between 1.45 and 1.61. I will let you know when it stalls. Should we check fuel pressure?
Expert:  Amedee replied 11 months ago.

I would..

Customer: replied 11 months ago.
Mechanic just told me that as the car gets warm it is stalling less
Customer: replied 11 months ago.
Could a code P0480 cooling fan circuit caused this stalling?
Customer: replied 11 months ago.
Fuel pressure is within spec. Car has not stalled for the last 10 minutes
Expert:  Amedee replied 11 months ago.

ok good

Customer: replied 11 months ago.
Here's what we found. Car was getting hot. Were able to control fans from scanner no problem. not coming on from temp. Unpluged ect and fans came on. Is there a way to test the ect?
Expert:  Amedee replied 11 months ago.

You can ohm it out or just look at the temp reading on the scanner and make sure it matches the engine temp

Customer: replied 11 months ago.
ok the car is throwing a p0118 and p115 code. as soon as I put a load on the engine it wants to stall when hot
Customer: replied 11 months ago.
the second code is p1115
Expert:  Amedee replied 11 months ago.

Thats probably because you had the ECT disconnected

Customer: replied 11 months ago.
Ok we have the car stalling. The Map sensor goes from 1.4 to almost 5 volts when the car stalls. Is this normal? Also when the car stalls it sounds like it is sucking air
Expert:  Amedee replied 11 months ago.

It sounds to me like you have an air or a vacuum leak.

Customer: replied 11 months ago.
we have a vacuum gauge on the engine now and it has about 18-19in hg at idle
Expert:  Amedee replied 11 months ago.

I am going to leave this question open.

Customer: replied 11 months ago.
thanks for your help. hopefully someone with more knowledge will take over.
Expert:  Tool Hut replied 11 months ago.

Hi, My Name is ***** ***** for posting your question to just answer. I am a ASE Certified Master Auto Technician with 20 years experience. I am confident we can resolve your problem together.Please remember I don't know your skill level. I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies to get to a satisfactory resolution.I also try to give all of the information you may need expecting a positive rating.

Do you have the air cleaner ducting installed? Have you attempted unplugging the MAF and see if it still stalls?

Customer: replied 11 months ago.
Actually I believe we have solved the problem. We replaced the ignition control module and it has yet to stall. Thank you
Expert:  Tool Hut replied 11 months ago.

OK. Let me know if you need further assistance

Expert:  Tool Hut replied 11 months ago.

It has been a couple of days since I have heard from you. Do you still need assistance? I have also noticed that I have not received a rating from you. If for some reason you question did not get answered please reply. I am only compensated for my time when you leave a positive rating. Your understanding is appreciated.

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