New to Stangs -95 Trans problem

Hi guys, it's not hard to tell that I'm a car guy but I'm not familiar with Stangs. My son has a 95 V6 Auto that his mother bought him when it was new. He now has a Check Engine light on and keeps having a problem with shifts. He has the tranny rebuilt with no relief.

Do these have a sensitive adjustment like the GM TV cables, or am I on the wrong track. Last night was the first time I had seen him or the car in a few years due to him moving out of state, but I'd like to help him out. I know those problems are vague, but if anyone knows a common problem associated with these I'd appreciate it.

Thanks, Axe

Sorry, it's a 94 not 95.

I printed all the code info Skymarshall linked in the OBD-II post. It's about 95 mi round trip so I can't get back out to see him until next week, but I'll check it out ASAP.

Axe