The car idled fine at 500 to 600 rpm for the longest time. Last week I started to get a light bucking upon acceleration. I pulled the distributor cap and found carbon fused to 2/3 of the rotor tip, pitted cap contacts and almost zero point gap in my Mallory dual point setup. I replaced the coil, cap, rotor and gapped the points. Problem solved car runs beautiful except the idle jumped up to 800 rpm during my test run. When I pulled into the driveway it suddenly dropped to 500 I stepped on the gas and the idle jumped back to 800.

I took the exhaust manifold temperature during the misfire episode and the temperature was off the charts; gas was probably burning in the exhaust manifolds. The temperature is now back to normal Right side 496 / Left 538. I didn’t touch the timing, my rationale was if the timing was right before I re-gapped the points it should be right now. I’m wondering if excess fuel vapors accumulated in the crank case and were being pulled into the carburetor by the EGR valve. Any ideas 🧐.

1955 312 T-Bird Warwick, NY

Ahh, but the change in point gap DID change the timing.  About 1 degree per .001 change in point gap.  Opening up the point gap would result in advancing the timing.

John - "The Hoosier Hurricane"

Make sure you don't have a problem with the distributor advance mechanism.  If it binds or hangs, it can cause an erratic idle. 

While I understand you did nothing as far as the carb linkage is concerned, I would check it to make sure it is not binding somewhere


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Good advice all, many thanks 🚗.

1955 312 T-Bird Warwick, NY