OK i am pretty new to this lt1 motor i have in my trans am, which i got this summer and rebuilt . I was wondering what should be the idle on a stock 1994 trans am, mine i belive is 500, is that too low because when i start the car soon after when the rpm drops from the disengaging starter it will flutter out, but when i give it alittle gas and warm it up it will run fine. so i am not exactly sure whats wrong, it just started acting up last week, as far as on the road after it's warm there is no problems, the motor runs nicely. its just when its cold.

 

Stock idle speeds, fully warmed up coolant:

M6 - 800rpm
A4 in neutral - 650rpm
A4 in drive - 550rpm

When the coolant is cold (24degF), idle speed can be 1,000rpm for the M6 or for the A4 in neutral.

 

so 500 is way to low huh

 

Sounds too low, particularly if you are reading it off the stock tach, wnich in many cars reads 100-200rpm higher than actual speed. Are you saying it only happens when the engine is cold? When its warmed up, it idles at the correct rpm?

Might be a problem with the coolant temp sensor in the water pump housing. If its not telling the PCM the coolant is cold, it isn't going to know its supposed to bump up the idle rpm, and run it rich for cold start. Or possibly the IAC passages in the throttle body are dirty and can't flow enough air.

 

yeah exactly it will only sputter when it is cold. after it warms up it will run 500-600 rpm fine