Auto Parts: high idle, wd40, gasket

Question
Replaced intake gasket on 91 blazer 4.3. Run fine till it got hot, then it started running really high rpm's. Changed all the sensors on top of engine (with used parts) Got same outcome. Any help would be appreciated!! Thanks! SS

Answer
Did you put a good rope seal of RTV on the front and rear of the intake before putting it back on?  If you don't have a good seal in these areas, you can get unmetered air into the intake which could cause the problem you describe.

One way to check for leaks without removing the intake again is to spray some WD40 around the front and rear of the intake and listen for an RPM change.