The truck is a 1992 K1500 w/ 4.3l v6 5sp manual. The truck remains at high idle (1900 RPM) even when it is warmed up. If i shut the engine off, then restart it (when parked, after a reasonable drive to warm it up) I get a more normal idle speed of around 900 RPM. This is odd. The check engine light illuminates upon starting and will go out after I get on the high way and am traveling at highway speeds. It comes on again when I let up on the throttle to exit the highway. I've checked for vaccum leaks but can't find any around the TBI body. I'm thinking I may need to change the base gasket on the TBI since I've never done it and it could be getting old and cracked. If it were cracked I would suspect that I'd have a high idle all the time rather than have the vehicle go to a low idle if I restart it after it's warm. I'd be interested to know if any body else has dealt with this.
re5513