Ford Muscle Cars Tech Forum banner
1 - 3 of 3 Posts

·
Registered
Joined
·
525 Posts
Discussion Starter · #1 ·
I've got a question that's bugged me for awhile. What causes an engine to run faster as it heats up? My 352 runs normal at startup. It will idle up on the the fast idle cam on the carb and as it warms up and the choke opens it idles down like its supposed to. Then after a few miles it will idle up way too fast. Like about 1300 or 1400 rpm
 

·
Registered
Joined
·
10,342 Posts
First, it could be the choke is opening too soon, and the curb idle screw has been adjusted up to keep it from dying when the choke comes off. But then it's too fast when fully warmed.

If it really is working right then it's most likely sticking throttle linkage, sticking throttle shaft, stuck PCV, intake tract (carb, spacer, intake) vacuum leak due to heat warping, etc. You need to find where the extra air is coming from. Spot-spraying with carb cleaner, brake cleaner, or even Windex, water, or almost any light liquid is good for that, and you know you've found the leak when changes engine sound. BTW - if it's a vacuum leak, the increase in RPMs also indicates the carb is adjusted too rich at idle.

David
 
1 - 3 of 3 Posts
Top