Mis-Fire Mystery

[RastaRobb]

Hey Fellas,

My '84 350 is missing on a cylinder when idling, and I can't figure it out. New plugs, cap, wires, rotor, air filter and even fuel filter.
All 8 cylinders are right at 150 lbs. of compression.
Checked the timing.
Put timing light on all cylinders, and all seem to be firing properly.
Yes, I rechecked the wires and firing order (5 times rechecked).

Can't think of anything else. Ideas?

[RastaRobb]

Opps, meant new fuel pump.

[lindstromjd]

I don't suppose you looked at the weights and springs on the distributor when you did the rotor? That's about the only other thing I could think of. Or that the vacuum advance might not be working properly...

[jjzepplin]

Isolate the bad cylinder. It's probably a Broken rocker or spring. Pull the valve covers and watch while it's running.

[bilfman]

Run it in the dark and look under the hood at all plugs wires and boots. Make sure you are not sparking anywhere. This is an easy first start. I have seen a brand new boot leech spark to a manifold , creating a miss.

[RastaRobb]

Good stuff--I will try all those ideas. I am thinking distributor, and looked at springs/ weights but was not thorough at all.
Thanks fellas

[craig113]

Possibility that there might be a cracked porcelain on one of the plugs from installation, Have done that myself once.

[RastaRobb]

I have had all the plugs in and out several times (checking compression and such as that) that I worried about that too. They all look good.

Got a new Distributor on the way, so we will see if that does the trick.