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Long ongoing annoyance

G

GOGOPONTIAC

New member
We bought our 04 Grand Prix GT back in 07 with 55,000 miles on her and almost from day one it had a very slight starting problem when the engine is warm. Cold starts no problem but when starting from warm or hot you have to give it some gas before it catches and runs. Once its running it is smooth and never acts like its going to die.
I just did an oil change at 101,000 miles and the air filter was very dirty to say the least. Had big dirty stain in the middle and some leaves in the plastic tunnel. But i don't think this the real issue. Maybe an o2 sensor? Your opinions greatly appreciated.
 


take the tb off, clean the back side of it. the walls and the back of the butterfly flap the sides of the flap too.
 
good old carb cleaner and a rag works fine. its cheap too. you'll end up using the most of the can. its all the black carbon coating you want to remove, clean till its shiny.

04 up have a o ring gasket. it should be re usable if it comes off clean.
 


While it may be a bit premature without taking the sensor or throttle body completely off i was able to clean some carbon out of it and spray all around the butterfly. I plan on buying the special screwdriver for removing the sensor so i can safely rotate the butterfly and clean much better.
Car turned over several times and gave it some gas it revved and dyed then started right up on the next key turn without the gas pedal so i know i am on the right coarse. Yes i am very cautious we just bought an 09 G6 with 41,000 on her and she is very clean inside and out so we have car payments again.
 
you dont need to remove the TAC to move the butterfly, just use your thumb, the stepper motor/gearing has no problem with it.

try not to spray into the tb/blower, spray the rag and wipe, repeat till whole rag is black.

spraying the solvent in there is likely to push that carbon into the TB shaft bearings.

also id suggest the fuel filter. the deadhead cars love to boil the fuel away inside the rail. when starting your car, turn the key to on for 2-3 seconds, then off then back on for 2-3 seconds, THEN start cranking. if it starts and catches and runs fine without throttle then its just vaporlock, a new filter will help fuel get to the rail faster as the injectors fire and release the fuel vapor into the engine as the fuel finally gets to the rail.
 
Update. Last weekend cleaned TB more throughly and also MAF sensor. Hot starting problem has never come back since 1st cleaning. Wish i would have known more about this years ago. In my younger years i worked on cars belts for each pulley,block mounted fuel pumps,set points and installed new rotor and condenser ......you get the picture, old school stuff. Time to go back to school.
 


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