98 K3500 W/p0507 Code

[skills4lou]

High all,

My 98 Chev K3500 7.4Vortec has been popped up code P0507 (High idle rpm) twice now. I thought initially that it was just a dirty IAC, but after cleaning it the problem still popped up again. It's idling at 800-900rpm, drops down to ~650 when I drop it into gear but keep it stopped with the brakes.

 

I also sprayed carb cleaner around the intake looking for a vacuum leak, but couldn't find anything that way. I recently had the upper intake plenum off for replacing the fuel pressure regulator, so maybe it's the gaskets there? I'm gonna get a new set tomorrow, and also replace the vacuum line for the FPR, but does anyone have any other areas that I might look for problems?

Thanks!

 

Skills