Well mine is a 5 speed so idk about the d4 stuff but I am getting tired of trying to track down the problem so after I do get It fixed I will more than likely put a cheap diy paint job and sell it. I think I will buy me a stock mustang to drive back and forth to work and drive my turbocharged mustang gt on the weekends.

 

If you want help, post your own thread. It's too confusing to try to respond to separate problems in same thread.

good luck

 

Ok new symptoms.
Well I replaced the distributor, new plugs, new plug wires, cleaned all the positive and negative battery cables, The car ran ok for a couple of trips but today the tach started going crazy again and after running like crap for about 30 minutes I limped into a parking lot. When I stopped in the parking spot the car died and smoke started coming from under the hood. I popped the hood and noticed the catylatic converter was bright orange so I figured the converter was stopped up. I cut the converter off and tried to crank the car and it will start for a second but die right after. Only code the ecu is throwing is #20

 

A code 20 is for the electric load detector. I would suggest downloading the 94 shop manual from one of the links in the Online Manuals thread in the main DIY section. Page 11-54 has some electrical tests to try. It is strange that you had a code 21 then code 20.

The cat glowing orange is due to the car running rich. The fuel is burning in the catalytic converter causing it to glow from the heat.