Car idles at 1,500?

[EclipsingJAX]

I drive a 97 gst with a 50 trim with supporting mods. I come out from work to start my car after 6 hours in the sun and realize that the car is ideling at 1500 rpms and wont go down. I drive the car home and park it and it starts to rev from 1,000 to 1,500 on its own. Throttle cable is intact and there are no loose vacumn lines. I have an eprom ecu with the stage 3 chip for 780's could the chip have gone bad in all this heat? Any suggestions to the causeof this problem would be appreciated.


Thanks

 

[zilo900]

check the biss screw, or completly reset it anyway because sometimes it moves around on its own. tighten it all the way, not hard just until it stops. then loosen it 1 and 1/4 turns. see how that goes.

 

[blcknspo0ln]

check your TPS

 

[GSTurbo05]

check your TPS

Its none of those, its gonna be your idle air control motor. Thats the reason why your revs are jumping. Try disconnecting your idle air control motor while the car is on and see if the rpm's change if not then your motor is dead and replace it.

 

[steve]

Try disconnecting your idle air control motor while the car is on and see if the rpm's change if not then your motor is dead and replace it.

Since disconnecting the ISC doesn't cause the ISC pintle to do anything unlike some cars where it might retract to it's home position thet test isn't conclusive that the ISC is bad. You have to measure the resistance of the coils to check the ISC and if within spec then check that the ISC homes when you first tunr the ECU on to make sure the drivers aren't blown.

Steve

 

[GSTurbo05]

aahh kool but the only reason i said that is causseee i had the same experiance and replacing my idle air control motor helped but thats my car.