Thread: 2005 Grand Prix chugging

Can you point me to some of these threads? I'd like to read too.

Once in this condition, I can stop at a stoplight, and bring up RPM's against the brake. It will chug and miss, but there is no way it should be thinking about shifting. Restart car, bring up the RPM's against the brake again, and the problem is gone!

No codes for me.

I have the same problem. I have a 2005 grand prix and will randomly have sluggish acceleration. The problem is temporarily fixed when I shut off the engine and restart it. Does anyone have a solution?

To Wolverines,

Yes, I am still trying to figure my 05 Grand Prix out. I originally posted this problem late last year, without any fix. I don't have a clue as too why the car is doing this. It appears that its a 2005 model issue! It's pissing me off too.......

I see in another thread Poseidon215 has the exact same problem with his 05. Whatever this is, it seems unique to 05's.

UPDATE: - It doesn't appear to be the MAP sensor. Disconnected it last weekend, and it's had three incidents since then.

Has anyone with the problem had their PCM flashed by GM? There are a lot of updates since 05... I'm half toying with the idea of an Overkill PCM to see if that fixes it.

Check this out... the basis for my theory above:

Service Bulletin
File In Section: 06 - Engine/Propulsion System Bulletin No.: 04-06-04-078 Date: October, 2004


TECHNICAL
Subject: Hesitation, Roughness, Light Chuggle or Check Engine Light, DTC P0300 (Reprogram PCM)
Models: 2004-05 Pontiac Grand Prix
with 3.8L Engine (VIN 4 - RPO L32)
Condition

Some customers may comment on a hesitation or engine roughness with or without the Check Engine Light illuminating. Upon investigation, the technician may or may not find code P0300, Random Misfire Detected. In some rare cases, the customer may comment on a light surge or fishbite when crowding the throttle with the TCC applied.
Correction
if a DTC code P0300 is set, follow the diagnostics in the appropriate Service Manual. If the diagnostics do not lead to a solution or if no DTC code is set, then reprogram the PCM. A new calibration has been released to address this concern. The following tables show the calibration number for reference, program the PCM with the appropriate listed calibration, or later, for this condition.

...funny how I couldn't find much on this a few weeks ago, and now google turns up all sorts of results:

Grand Prixs Of North America • View topic - Does anybody else have this accel. problem

I'm getting an Overkill PCM!!

Old thread, but thought it worthy of an update.

I had the stock PCM reflashed to the updated code mentioned in the TSB. It's now been months, and not a single problem since, so this fixed it for sure. Even better, the car now feels as strong as my old 99 did. I always felt I lost some power when I traded my 99 GT for this 05 GT, and now I've got my missing power back too.

Happy New Year folks.

What did you have to pay to get it reflashed? This problem just happened to me again today.

Hey Surferstick......

Thats awesome on the fix. It's been a real pain for me and many others. I just now read your fix and was wondering (Like dsanchez) how much $ and if you had to go to a dealer to get the reflash??

Thamks Again.........

Steve

Hey Wolverine.......

Just saw you were having the same issue that I have been having with the 05 Grand Prix. I recieved a fix from another memeber that I wanted to pass along to ya:
Old thread, but thought it worthy of an update.

From surferstick:

I had the stock PCM reflashed to the updated code mentioned in the TSB. It's now been months, and not a single problem since, so this fixed it for sure. Even better, the car now feels as strong as my old 99 did. I always felt I lost some power when I traded my 99 GT for this 05 GT, and now I've got my missing power back too.

Happy New Year folks.


I haven't gotten mine flashed yet, but will check into it.

Just wanted to pass this along to ya.

Later....... Steve!

Hey Gorecki,

Just saw you were having the same issue that I have been having with the 05 Grand Prix. I recieved a fix from another memeber that I wanted to pass along to ya:
Old thread, but thought it worthy of an update.

From surferstick:

I had the stock PCM reflashed to the updated code mentioned in the TSB. It's now been months, and not a single problem since, so this fixed it for sure. Even better, the car now feels as strong as my old 99 did. I always felt I lost some power when I traded my 99 GT for this 05 GT, and now I've got my missing power back too.

Happy New Year folks.


I haven't gotten mine flashed yet, but will check into it.

Just wanted to pass this along to ya.

Later....... Steve!

Hi davisg,

I didn't know if you still had your Grand Prix or not, but had another member on this site reply that he finally found a fix to that Chugging that we both were having with our Grand Prix.

From surferstick:

I had the stock PCM reflashed to the updated code mentioned in the TSB. It's now been months, and not a single problem since, so this fixed it for sure. Even better, the car now feels as strong as my old 99 did. I always felt I lost some power when I traded my 99 GT for this 05 GT, and now I've got my missing power back too.

Happy New Year folks.


I haven't gotten mine flashed yet, but will check into it.

Just wanted to pass this along to ya.

Later....... Steve!

I think it cost $60.00. It wasn't much anyways.

Originally Posted by surferstick

I think it cost $60.00. It wasn't much anyways.

I just got quoted $120 at the local dealership...

Please let me know if that works for you. Thats if you get it done.

Thanks for keeping me updated.

Worked 100% for me. Never did any crazy chugging since. Worth every penny.

I've been waiting awhile to reply to this thread, I tried a few things and haven't had a chugging incident since.

Cleaned the throttle-body, changed the thermostat and did an oil change and put in a leak stopping agent. I've been trying to wait it out for about two months now and see if any of these items would work and apparently one of them did.

I"ve had similar symptoms, when plugging into the computer I found out my Intake air time is reading 38-40deg C (100deg F). Looks like the sensor is also part of the MAF unit.

It's unfortunate that if this is a known issue, it's so expensive to fix....(120$ to reflash code that's screwed up from the factory)