Check for leaking vacuum lines, especially to the throttle body and idle control valve.
Check the timing which should be 12 degrees bfore top dead center. Timing marks oare on the crankshaft pulley and lower part of timing cover, near crankshaft pulley.
The mixture reqires that the CO level be tested at the exhaust. I realize this is unpractical for you and I am giving you tests for that, Idle speed switch and all diagrams that I can find with any adjutability.
Idle is a mixture of many sensors and eventually the ECU. So, you may want to check the fuel pressure if you have the means if you continue to have trouble.
I am giving you everything I could find.
If you have any questions or need any further help, lease let me know and I will walk you through evrything that can be done with the means you have.
Images (Click to enlarge)
Tuesday, October 11th, 2011 AT 9:33 PM