What causes my engine to idle very high? on 2005 GMC Savana 3500

Tried MAF sensor, upper intake gaskets (possible vaccum leak), IAC (had to change whole throttle body can't buy IAC alone). Unable to find any vaccum leaks.

by in Flint, MI on July 12, 2011
1 answer
ANSWER by , July 13, 2011
Check the alternator.