High throttle miss

[Texasdoc]

Originally Posted by marklotus

My Cobra did not want to rev over 4,000 RPM. It was fine at low RPM but under load at higher RPM's it would sputter and break up. I had the car at a high performance Ford shop and they tried everything...battery, carb, coil, plugs, valve adjustment, valve springs, ignitor and other stuff that I forgot. They tried everything and nothing seemed to work. Eventually they found that someone had tapped into the coil wire for the electric choke. At higher RPM's the voltage wasn't there for what the coil needed to fire properly.
A very simple fix but a difficult to find problem.
I hope this saves someone a lot of frustration.

No choke

The only two wires going to the coil are straight from the new MSD box.

I am borrowing a carb tomorrow to see if that helps. It is an Edelbrock 500, which is a little small, but should at least tell me if my Quick Fuel is the source of the miss.

I rerouted the plug wires further away from the alternator, twisted the magnetic pickup wires to the distributor (I have the shielded extension cable), twisted the coil wires, made sure the coil wires were not anywhere close to other wires - all in an attempt to shield from EMI. Coil wires are on the opposite side of the motor - away from the pickup wires. Plug wires 1&3 are separated, as well as wires 5&6. I ran it with the fan on & off. Air cleaner on & off. Still misses.

Another problem is this heat and humidity. I only have about two hours in the am before it gets too hot to work on it. I'm getting too old to be working in the 100 degree shade. Is there a pulling my hair out emoji?