I just replaced my 1995 blazer's fuel injector and it was fine. But I noticed that when I put my truck on park the RPM jumps up to 2 and it stays there but if I out the truck into another gear such as drive, the RPM will immediately drop down to 1. I know this is abnormal behavior, can anyone share there thoughts on what is going on with my truck? Thanks.

 

Obviously, you mean 2,000 RPM, and mine (2001) will run at higher RPM also until the engine is warmer or you put it into gear. I believe that this is normal, but could very well be wrong...

 

Sure sounds like an abnormally high idle to me. The PCM should control idle at somewhere around 650-750 when cold and 550-650 when up to operating temperature. when in gear, it is normal for the idle speed to drop slightly.

As a start, check for vacuum leaks.

 

Mine (2001) will idle at 1.2k until warmed up then runs around 600.