Imperial Pain

IMPERIAL PAIN
Hi Rick, Hope you can help with a
frustrating drivability problem with the
girlfriend’s 1972 Imperial, 440, all stock.
After about 20 minutes of normal driving
it starts idling rough and then stalls. It
is then very hard to start, but if you wait
10 or fifteen minutes it will start and run
and the process repeats. There is fuel in
the carb when this happens (acc. pump
squirts anyway). Seems worse the hotter
it gets (engine temp and ambient). I’m
thinking vapor lock? I replaced the secondary
ignition, ignition module, fuel filter
and pump, rebuilt the Holley carb (disabled
the bimetal lean out thingy), can’t
find any vacuum leaks. The idle is not real
smooth even when cold , but then it deteriorates.
Other than that it’s a great, well
preserved old land yacht … if only I could
afford to drive it.

I’m thinking pickup coil. you have
proven that it isn’t a fuel delivery problem.
Second choice: Ignition coil.