I've been having a sporadic missing issue for about a week now and I cannot figure out what it is? I am cheap so I started with the things that were the cheapest to repair. Just ordered a new distributor cap and rotor, but here are the other items I've already checked.

- Checked the valves. I had just done my first valve adjustment and may had screwed it up - looked fine
- Tested the injector and cleaned it out - appeared to work fine?
- Replaced the spark plug. Solved the problem, but only momentarily.
- Checked for signal to the spark plug by putting one of those lights in the spark plug circuit. Looked OK. Any chance the spark from the dizzy is not strong enough?

Next solution is to install the new cap and rotor on the distributor. Did I miss anything?

If you have points don't forget the condenser, A arching sparkplug wire can cause

a miss.

Clean all your grounds...
under the relay board
Tranny ground strap
battery terminal and bolt to body

***** Under what conditions does the problem accrue be specific please.

Vance it really sounds like you have a bad connector somewhere. Do you have enough slack with your spark plug wires to swap the one on the bad cylinder and see if the problem follows the wire? Jeff already mentioned the ground cluster. The other electrical I would be checking is the lead to the injector. This can be done by removing the connector to the ECU and putting an ohm meter across the appropriate connectors. Should be low resistance. Have a helper wiggle the wires and see if you get jumps on the meter.

Thanks for the help. It does appear to be electrical and very random. It has been very hot around here and could be heat induced? Having recently pulled the motor I cleaned up all the grounds and they should be good! I will check the points and condensor - except would bad ones only affect one cylinder? Will alse check the injector wires, except that the fuel delivery seemed OK when I pulled the injector? Not sure about the slack in the wires - will check and see if I can swap wires or borrow one and test it? Thanks again?

I agree about the points and condensor - hard to imagine how they would effect one cylinder unless that cylinder was already marginal.

The randomness really makes me think it is a bad wire. As you troubleshoot you disturb the wire and fix/break it.

Vance, the spark plug connectors have a resistor built into them. Use a VOM to measure all four connectors and see if the cylinder that is missfiring has a higher resistance then the other wires. You may have to do this twice, once with a cold engine and again when its hot.