2004 Grand Prix GT2 Starting Issues?

timg_98 · #1 10-04-2007, 10:12 AM

HI! My wife has been having starting issues with her 04 GP GT2 3.8ltr V6. The computer is not generating any codes at all. When she gets in it in the morning it normally does fine. However By lunch or later in the day it will start. It act's like it will start and the gauges will move, but nothing so she has to give it a little gas and then it will start.
Things we have changed. 1. Crank Sensor 2.Cam sensor also cleaned injectors. Sense there are no codes it is frustrating.

The scanner shows all injectors, fuel system, and everything else is working properly. My Brother-in-law (Certified Master Mech.) who lives out of town suggested looking at the Anti Theft system.. Does anyone have any Ideas? If it would just generate a code life would be great. Sorry this is so long.
Thanks in advance.
Tim

tblake · #2 10-04-2007, 10:49 AM

everytime someone says that to get it started we have to "tap the gas" my first gut feeling would be that the motor isnt getting enough air. I would maybe try removing and cleaning the IAC motor pintal as well as its bore in the throttle body. How long since the fuel and air filters have been changed? Maybe be a good place to start as well especially if they have never been changed.

Had a 2002 chevy venture come into the shop with a complaint that the AC doesnt seem as cold as it should. Found a leaking O-ring by the accumulator and a bad compressor seal. Replaced both but in the process of dong the accumulator, had to remove the air cleaner assembly. When I opened it and took a look at the filter it was completly black, and not like the filter element was dark, it was almost as it it were covered in tar, it was so dirty that you couldnt even see the filter element fins anymore, they were all fused together by this black build up. Unbelieveable how bad people let things get. Just out of courtousy I replaced it, but the customer didnt comment on if the van ran better or not. Im sure it did or at least they got better gas milage.

timg_98 · #3 10-04-2007, 11:21 AM

Hi TBlake,

We replaced the fuel filter about 2 months ago and I also cleaned the K&N Air Filter at the same time. The Air filter gets cleaned about every 10-15,000 miles. I have the checked the IAC motor pintal. I will check check and clean it as well. We keep it pretty well maintained, but there is no clue as to the shape of the IAC.
Thank's for the Suggestions...
Tim

ecartman · #4 10-07-2007, 11:23 PM

Quote:

Originally Posted by timg_98

Hi TBlake,

We replaced the fuel filter about 2 months ago and I also cleaned the K&N Air Filter at the same time. The Air filter gets cleaned about every 10-15,000 miles. I have the checked the IAC motor pintal. I will check check and clean it as well. We keep it pretty well maintained, but there is no clue as to the shape of the IAC.
Thank's for the Suggestions...
Tim

I had the same problem on my 04 model and have encountered it on quite a number of GM drive by wire throttle body vehicles coming into the shop. A good cleaning of the throttle body cured my problem (and the others as well). On drive by wire units, the throttle plate is the IAC (no separate IAC motor). Hope this helps.

tblake · #5 10-08-2007, 10:11 AM

hmmmm, didnt even realize that. Thanks for the info ecartman!!! I've never worked on a drive by wire vehicle, can you tell?

ecartman · #6 10-08-2007, 09:10 PM

Quote:

Originally Posted by tblake

hmmmm, didnt even realize that. Thanks for the info ecartman!!! I've never worked on a drive by wire vehicle, can you tell?

Yeah, I stumbled across this solution purely by accident when trying to figure out why my car was stalling. Please post if cleaning solves the problem. Thanks!

eippermx · #7 10-09-2007, 07:35 PM

I've got 155K miles on my '04. When it had 60K on it, the same problem you had started manifesting itself. I cured it with cleaning the throttle body. I'd highly recommend getting rid of the K&N and going back to an OEM or an after market filter. I bet that is your problem. I can show you a photo of a throttle body that had a K&N on it that has oil residue inside of it. Do a search on this website. You'll see both sides to the K&N issue.
BTW, I clean my TB every 35K miles. No problem since.

timg_98 · #8 10-11-2007, 11:11 AM

I will try cleaning the throttle body and change back to the stock air filter. Never even thought of that.... I will post results. I hope to get to it this weekend supposed to be nice out. Stormed last week could not get to it at all.

Thank you everyone for your help.
Tim

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