Vacuum Leak?

1965-Mustang

New Member
Nov 25, 2003
85
0
0
I have been having a problem with my idle speed for a while now. Everyhting I have tried has not helped. And with my limited knowledge of carburetors I am at a loss. I have pretty much figured that it is a vacuum leak, I have tried the carb cleaner trick but really am not quite sure still. I think the carb cleaner made the engine bog down when I sprayed at the base of the carb where it contacts the intake. I tried tightening down the bolts but did not want to go to hard on them in fear of messing up the base.
What I have noticed while driving it is this; it will sometimes idle fine at 800-900 rpms in my garage, sometimes the idle speed will just decline slowly until it cuts out and dies, and when it is in this state I usually notice smoke out of the tailpipes, sometimes it will idle at 2000 rpms, this happens after i bring it up over about 3000 rpms or WOT. Also when I mash the pedal for WOT black smoke will come out of the pipes, so I figure that it runs a little rich...
I thought maybe this could be ignition? But I thought a vacuum leak was more probable.
Thanks