92 Silverado High Idle

Hello.

Have a 92 350 with 700R4. Start it cold idle "seems" OK. When it warms up it has a high idle when stopped at light (in drive)..I have replaced numerous things..TPS,IAC,MAP and even the ECM,..I have replaced vacuum lines around Throttle body...What else could be the problem?


Thanks, Pete

Hello.

Have a 92 350 with 700R4. Start it cold idle "seems" OK. When it warms up it has a high idle when stopped at light (in drive)..I have replaced numerous things..TPS,IAC,MAP and even the ECM,..I have replaced vacuum lines around Throttle body...What else could be the problem?


Thanks, Pete

TBI base gasket.
Under TBI.
Drys up and sucks air causing high idle.

You could have bought a couple hundred gaskets for what you spent throwing parts at in.

Let us know how it goes.