Strange Idle problem

[DSMNewbie09]

I have done alot of research on this site and it seems like no one has a simular problem.

When i start my car the idle is perfect for about the first half minute then the idle starts to drop and act like it is going to stall then after 2 and half minutes of the car being in idle the Rpms go back to normal and the car drives perfectly like nothing is wrong. if i turn the car of and then back on right away it starts all over again so it has nothing to do with the car being warm or not.

the TB has been cleaned.

I tryed ajusting the BISS which fixes the problem for the first 2 and a half minutes then it jumps up to 2 RPMS.

the TPS looks like it has no problem at all.
i have also tryed reseting the ECU but that didnt help either.

any sugestions will be helpful

 

[snakeyes711]

You could start by telling us what car it is. Have you checked for intake leaks on all the hoses?

 

[DSMNewbie09]

sorry about that... Its a 97 GST

Yes it the hoses were checked for leaks

 

[Prime85]

I have been having something similar

 

[snakeyes711]

Maybe you have something pulling voltage. that would make the rpms drop. Put a volt meter on it, and watch to see if somethings turning on to put strain on the system. Mine idles low when the fans come on until they kick off.

 

[1gAllTheWay]

i doubt this might be the problem but alternator maybe?

 

[1gAllTheWay]

or else its the tbs thats all i can think of

 

[2GeNTSi]

Have you checked your ISC?

 

[whe3ls]

sounds like it could be the idle speed control