1988 sierra fast idle
 

1988 sierra 5.7 engine c/k, I have a fast idle, I have replaced the IAC and the EGR. Need a direction to go next.

Jim

RE: 1988 sierra fast idle
 

Probably the tbi gasket....spray a little b-12 around the base while she runs...BE CAREFUL THOUGH...The stuff is flammable as hell!

RE: 1988 sierra fast idle
 

Thanks Much will give it a shot, is there anothor name for it, can not find b-12

Jim

RE: 1988 sierra fast idle
 

I believe he is thinking if you just spray something around the gasket area to see if the engine speed changes - any carb cleaner should work .

RE: 1988 sierra fast idle
 

thanks birddog, having a senior day.
jim

RE: 1988 sierra fast idle
 

Yes,carb-spray..B-12 is most popular..but most any brand..again,CAUTION..that stuff is close to pure ether.. the idle should change and you'll hear a sucking sound if the gasket is blown.
Fairly common on Tbi trucks

RE: 1988 sierra fast idle
 

ok thanks argon, you guys have me straight now, love this internet
Jim

RE: 1988 sierra fast idle
 

replaced tbi gasket, this solved my problem
Thanks
Jim

RE: 1988 sierra fast idle
 

Cool...glad she purrrs now!