Need help pls - probably dumb ?
New User
Joined: Jan 2003
Posts: 2
Likes: 0
From: Richmond
Need help pls - probably dumb ?
I have a 91 F-150 w/ a 302. It recently started idling at a higher RPM (around 1200) and is making a fairly loud hissing sound only noticeable at idle. It's probably something simple, but so am I.
So far, it still runs okay while driving. Any ideas or help would be greatly appreciated!
Thanks
So far, it still runs okay while driving. Any ideas or help would be greatly appreciated!Thanks
Senior User
Joined: Oct 2000
Posts: 187
Likes: 0
Need help pls - probably dumb ?
part of the upper plenum gasket might be leaking sometimes they get pushed out or sucked in or could be a vacuum hose off.also maybe your throttle plates aren't coming back to a close all the way
Junior User
Joined: Apr 2002
Posts: 97
Likes: 0
From: Arcadia US
Need help pls - probably dumb ?
It is most likely nothing major. The first thing that comes to mind is that either the vacuum hose that plugs into your brake booster it with cracked or fell right out. Check your engines vacuum at idle it should be about 17-20 psi.
