Frankenstein318

Whoa! Timing will NOT make one cylinder run different than the rest! (Unless you have an inaccurate distributor - rare, and can only really be seen on "Raster" view on an ignition scope... unless you take other steps, which I won't go into, because it's SO unlikely.) That cold exhaust manifold runner is a big clue for you. It bears inspection. It's indicating a problem with that cylinder.

Someone suggested a compression check. Yes, do that. Another not-so-hard diagnostic is a "power balance" test. Do this by shorting each cylinder individually and watching/comparing RPM drop for each cylinder. They should all drop equally, or very nearly so. If you're cold cylinder drops significantly less or not at all, you have to figure out why.

First thing I'd probably check on the cold cylinder is the intake runner to it, looking for a vacuum leak. Open vacuum source holes or broken vacuum hoses. Even the intake manifold gasket can have a leak. If you find no other leaks, spray a little squirt of carb cleaner where the intake runner meets the cylinder head. If the RPM rises and/or the idle smooths out, voilá!

Another poster suggested dist. cap and/or wires causing intermittent misfires. Yes, highly possible. Do you know how to check for carbon tracks in the cap and through the rotor? Sometimes those are called by excessive voltage demands of high-resistance plug wires. Have an ohmmeter? Check the plug wires on the cylinders that fail the power balance test.

There are only about 393 other things it MIGHT be, but these diagnostics are the best place to start.

Keep posting with your findings. I'll subscribe to the thread and see if I might be able to offer further ideas.

JD
(former ASE-certified driveability tech, currently a piano technician! what a life)