Ford Repair: 94 mustang conv shifting and idleing problem, vacuum lines, water intrusion

Question
I just bought a 94 mustang Conv with 67k. It was running good for about a week. I power washed the engine and it seemed to run fine that day. I live in New england and it started raining the next day. 2 days later I was driving to work in the rain and the car seemed as if the cruise was on. I pulled over shut it off and started it and the engine reved to around 3k I put in gear to try to drive it off but i noticed that i was running at 3k and about 55mph in second it seemed the tranny wasn't shifting. I pulled off again shut it off and tried to start it but it just cranked. I put the pedal to the floor and it started. It was at 3k again and i put in gear it took off with a screach and then the check engine light illumiated. I pulled over again and sat for about 20 minute and then tried to start it and it ran fine. I nursed it home and it seemed to stick on the throttle but back off and shift okay. I then let it sit till the rain stopped (about a week) and started it it seem to start fine. I drove it but it had the same problem. it seemed as though cruise was on at around 3 k and it wouldn't shift out of 2nd. Is it wettness or some thing in the computer?

Answer
Hello and thanks for the question ...I'll try to help.
I would certainly have the computer checked out for fault codes. It might be water intrusion in one or more of the system components that could be having a problem. As far as your transmission NOT shifting goes....I believe that the transmission in your car is an A4LD. I would check the engine to make sure that you didn't power vash any of the vacuum lines off of their nipples at the engine.......especially the one to the vacuum govenor at the transmission.
Hope this helps,
Erik