I cannot pull DTC's from 1991 2.3 Vert

Hello, I am new here, and i just bought a 1991 2.3L Mustang Convertible. I already have a 1993 2.3 Convertible, so I bought another for my kid.

The problem is the car was sitting for a few years. A guy bought it and rebuilt the tranny, new radiator & battery. I get it and it ran rough, engine light, and tach jumping around.

My other 1993 had the same symptoms and I pulled the codes and the ignition module was bad. I replaced this 1991's module, and nothing got better except the idle.

I have a snap on scanner with the correct software. I can read the sensors as live data, but I cannot get it to run the self tests to give me the codes. The scanner works. Does anyone have a suggestion what to check to see why the scanner is not reading?

thanks

whoever reminded me of the basics, kudos to you.

I did get to pull the codes based on the information linked to a ranger website. Thanks.

I had EGR codes, which once I cleaned the egr and pulled the stuck valve open with a vacuum pump the code did not reappear. However...

Today I managed to pull the plugs (with only damaging one wire). Each plug was so worn (75 thousandths gap). SO I performed a bandaid regap and clean to diagnose the performance. Amazing difference the basics make. The driver side plugs are a ****** to get to when the wires are stuck on.

So far so good.

However, I have a new, and doubly tested at two locations, ignition module. And the tach is still reading flaky. Any other suggestions?

Well autojoke, or I mean autozone will only do the test a couple times...that is since they have cut their staffing to a manager and one employee. The line of people has not changed for hepl at their store, but their service sure has declined.
My 1993 vert took about 8 times to show the fault, but this time they would not test more than 4 times.


Still the car is running better, and the engine light will reappear, just when my daughter is driving it. I need to pull itback t oread the codes again.