I was getting high idling while driving not while starting up found that the Trottle Sensor was bad again ,I had replaced the Trottle Position Sensor and Idle Control Valve back in March 2013 due to rebuilding just put everything new. I'm now getting a high idle when starting up after replacing Trottle sensor again. Would it be the Idle valve to again.
High Idle on start up on 1999 Ford Expedition
by 915tommyboy74 in El Paso, TX on October 23, 2013
ANSWER by pushrod , October 24, 2013
Possible vacuum leak.
ANSWER by globalhelper , October 24, 2013
agree with pushrod or tps is misadjusted
ANSWER by milesauto , October 24, 2013
You may have a vacume leak causing the fast idle. Also have seen a stuck PCV valve cause this a few times.