The charging circuit wouldn't effect idle speed any, unless there was a very large load on the alternator that would drop idle down 100-200rpm, but it wouldn't cause a high idle. I think you are right. It's a seperate problem.
As far as the high idle, check all the vacuum lines and the throttle position sensor. A vacuum leak most likely won't contribute to high emissions by itself, but it would cause a high idle. The throttle position sensor idle voltage should be almost exactly 0.96 volts. Other things you could check are:
intake air temp sensor. This sensor calculates how dense the incoming air based on it's temperature.
Whether the throttle is closing all the way. Maybe a binding throttle cable. Do NOT adjust the little screw that rests against throttle. That is factory set. The computer is responsible for idle speed based on the input of various sensors. Let us know.
Sunday, January 20th, 2008 AT 4:47 PM