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FIXITMAN
FIXITMAN, Mater Technician
Category: Pontiac
Satisfied Customers: 17143
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH
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I have a 2004 grand prix with a 3800 engine, it starts fine

Customer Question

I have a 2004 grand prix with a 3800 engine, it starts fine and runs great for about 1 minute, then about when i get to the road i press down on the throttle to go and it stalls instantly, i let it sit for about 1 minute and it starts again but does the
exact same thing, i can floor it and it takes off everytime, but it just stalls if i give it a little throttle. I changed the MAF, Crank sensor and complete throttle body with sensor. Fuel pump pressure is up about 50lbs.
Submitted: 1 year ago.
Category: Pontiac
Expert:  FIXITMAN replied 1 year ago.

Hello, my name is***** for the question. Can you tell me if the check engine light is coming on?

Customer: replied 1 year ago.
it was but i deleted 2 codes for a etest that we have to do every two years, and thats is when it started to act up, as i drove away from my shop. the two codes were p0107 Manifold Absolute Pressure and p0455 evaporative emissionsLeak detected, but the light has not come back on even with me driving it around a bit
Expert:  FIXITMAN replied 1 year ago.

Thank you. One last question. How many miles are on the car?

Customer: replied 1 year ago.
about 319,000 kms or 190,000 miles
Expert:  FIXITMAN replied 1 year ago.

If the engine is shutting down like that it is typically due to a failure in the fuel pump control or in the ignition switch. It can also be in the ignition module located under the ignition coil pack. Did you get that 50 psi of fuel pressure when the engine turns off?

Customer: replied 1 year ago.
I Rechecked it this morning and do still get 55 pounds of fuel pressure when it stall outs, so I'm guessing the fuel system is ok, my guess also that it is the coil module, I have had issues in the past with older cars with the modules , but wanted a second opinion before I keep spending money on it... Thanks
Expert:  FIXITMAN replied 1 year ago.

It does sound like the ignition module under the coil packs. You can remove it and most auto parts stores can test it for you. This is the most common cause. It can also be a relay issue or the ignition switch but that is not as common.

Customer: replied 1 year ago.
I put another coil module on including coils and it does the exact same thing, if I put foot on brake in gear and slowly depress throttle and let the car roll or even just drive without foot on brake the motor dies at exact same place every time, seems like about where it normally is at driving normally down the road, could it be the foot peddle sending unit is burnt out in one spot where it normal is and that is why it dies when pedal reaches that area
Expert:  FIXITMAN replied 1 year ago.

So it will continue to run fine if you give it some gas?

Customer: replied 1 year ago.
I can floor the car or idle it and its fine, but taking off you have to give it some gas at a stop sign and then it stalls instantly, does not miss, just dies
Expert:  FIXITMAN replied 1 year ago.

Does your scan tool read live engine data? If it does can you tell me what the ltft and stft readings are?

Customer: replied 1 year ago.
It does not have that reading, it only Says , Fuel system Mon. Ok
Expert:  FIXITMAN replied 1 year ago.

Can you see oxygen sensor voltage? If so can you tell me if the reasons are fluctuation and what the maximum and minimum voltages are?

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