engine Hunting on cold start
Thread Starter
|
New User
Joined: Nov 2011
Posts: 5
Likes: 0
engine Hunting on cold start
My 93 f150 with the efi 4.9 hunts, or i'll say revs, maybe, for about 20-30 seconds after starting when it's been sitting for several hours. Cold engine. It goes from a slow idle to fast and back to slow then fast again. It does this about 5 or 6 times for approximately 20 seconds or so After that it runs good and doesn't do it again until it's completely cold again. I have replaced the throttle body gasket and intake gasket when i resealed the valve cover. But keep in mind this hunting idle problem was there before changing any gaskets. Anyone have any idea what might be the culprit for this annoyance. No codes stored. Thanks
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Very common issue. The Idle Air Control (IAC) aka IAB can be gummed up or worn out. Here is some info: Fuel Injection Technical Library » Idle Air Bypass (IAB)
Another contributor is a vacuum leak(s).
Another contributor is a vacuum leak(s).
Thread
Thread Starter
Forum
Replies
Last Post
Red Raider 4x4
1987 - 1996 F150 & Larger F-Series Trucks
1
Oct 30, 2005 06:21 PM
