1999 Saturn SL1

Engine Performance problem
1999 Saturn SL1 4 cyl Front Wheel Drive Manual 76000 miles

The check engine lt. Is on, code 507. The idle speed goes up to aroun 2000rpm on start up for around 20 seconds, then drops to around 1200. If I accellerate at all, it goes back up and repeats the same thing over. The idle speed stays up between shifting as well. I know there are a number of sensort that can cause this code, any suggestions where to start?
October 13, 2009.

I would start looking for a vaccuum leak especially with that code. Start looking at the pcv hose that runs from the valve cover to the intake manifold its short and s shaped they get holes them and leak vaccuum very common. If thats not leaking then spray some carb spray around intake manifold gasket between the head and manifold and any vaccuum hoses while the engine is idling if there is a leak u will loose engine rpms might even die out. Start there then we will explore ur sensors. Let me know what u find.

Oct 13, 2009.
Clean the Idle Air Control Valve. It's on the throttle body below the throttle position sensor. The IAC is like a giant needle valve that has a 4-pin connector on the back side of the throttle body, nearer to the firewall. It's hard to see, often overlooked, but easy to remove, clean with a toothbrush and any spray type choke cleaner. It's held on by two torx-type screws. I can't remember what size--dropped and lost the bit.
I fought this problem for two months and spent over $300 on tools and parts only to fix the problem with $.25 worth of spray.

Oct 15, 2009.