I have a 1988 F150 with 302 and automatic and PS. It appears that the idle air valve is not getting proper voltage. I read 12.85 v from red lead to ground and nothing accross the leads. I tried a new valve that did not help. The computer codes read 15, 23, 33, 35. Could this problem be caused by the ECM or would something else cause the valve not to work. When I take my foot off the pedal at idle the engine dies. Some times the engine will run at very low idle speed if it has been driven a while.
Thanks,
Owen