Mis-Fire Mystery
 

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?

Re: Mis-Fire Mystery
 

Opps, meant new fuel pump.

Re: Mis-Fire Mystery
 

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...

Re: Mis-Fire Mystery
 

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

Re: Mis-Fire Mystery
 

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.

Re: Mis-Fire Mystery
 

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

Re: Mis-Fire Mystery
 

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

Re: Mis-Fire Mystery
 

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.