I've been trying to deal with this idle issue for longer than i'd like to admit. I have a 2002 Saturn SL2 1.9L DOHC and I've replaced the IAC valve, TPS sensor, and cleaned the throttle body, to try and get rid of the codes p0507 and p0509 but to no avail. engine will intermittently idle between 2000 and roughly 2300 RPM it basically will drive itself when i put the car in first gear all the way into 5 gear it will do it's best to keep the RPM's at 2000 I'm at my wits end and don't know what to do any and all help would be appreciated.

 

Interesting reading

p0509 - High Idle - Rpm - SaturnFans.com Forums

This is tagged as a p0509 post but there are a few 0507 comments tossed in.

Have you checked for vac leaks?

Note: the intake manifold gasket fubar issue was only an SOHC issue. That being said, you could of course still have a leaky intake manifold gasket.

Try some of the tests discussed in that thread to narrow down the possibilities in a logical manner

 

I have sprayed close to a whole can of throttle body cleaner around the throttle body, pcv valve, intake manifold, secondary air pump, etc... and no change in idle speed. only when i removed the air intake snorkle and covered the throttle body did the idle change, i used my thumb and covered the IAC bypass and didn't cover it all the way and then the idle sounded damn near normal. I'm thinking my IAC valve is stuck open making it seem like a really bad vacuum leak. Would greatly like to hear more thoughts on the matter.