Hi, This is my first post on the forum. I have a problem that I just can't seem to track down. My stock 352 motor is misfiring 90% of the time on one cylinder and about 30% of the time on another. It does so at any rpm and today I tried to track it down. I put my timing light on each wire to see if the misfire was electrical and it seems to be. I check the plugs and even switched two and the misfire stayed in the same cylinder. I put new plug wires on, same thing. Switched the plug wires but the problem didn't move. So I figured it is the distributer cap and rotor button. This seemed like a sure thing since the two problem cylinders are fired by adjacent positions on the distributer.

I put the new cap and rotor button on and the problem remains. I can't figure what to check next.

Some backstory that may help. The problem started after I did a complete tuneup including some carb work and compression check. I have rechecked the carb to see if the problem lies there, but everything checked out.

Any help is much appreciated!

 

You might want to check the routing of the plug wires to make sure they're all loomed properly, crossing each other cleanly and none are running parallel with while touching each other.
rx

 

Thanks for the advice on the plug wires. I had previously checked that in my troubleshooting.

Tonight, I messed with the points and restarted the engine. The problem remained but manifested in different cylinders. I changed out the points and condenser and the truck purrs perfectly. Problem solved!

I am curious to know why, if the points were bad, it was only affecting a couple of cylinders. Any thoughts on that?

 

Not sure why points would give you a same-cylinder miss.

Anyway, get rid of them:

Ignitor

Works up to 15,000 rpm, so no problem on your 352.....

 

Chances are it wasn't the points, but the condenser. Can't tell you how many times back in the day I've gotten a bad one straight out of the box.
Sometimes, just moving the wire to the condenser is enough to make the symptoms come and go.

 

Thanks for the help everyone. It ran perfect on the way in to work today.

I'll check out that ignitor system for the next time I need to work on the ignition.