Hi guys I hope you can help me. I have a 1994 STS- o sure it's 234,000 miles but I LOVE IT and don't want to give it up. I've babied it as much as I can, but jeez they charge you to work on an old one just like it's a new one! Anyway it's gotten to where it won't shift into high gear now- recently I replaced the alternator on it because it went bad and my friend said it might have been electrical caused by the bad alternator. I can shift it with the gear shift from 1,2 and 3, but it just slips out of gear when it should shift into high or overdrive gear. I had it in the shop once and they disconnected the computer and when they hooked it back up it worked! But then it started it again. My friend disconnected the battery once and it worked, but then it started doing it again. What do you guys think? Is this a electrical problem or is it something else? What do I look for? Is this something I can do myself (I'm pretty handy with the tools) or do I have to take it to the shop and if so what does it usually cost? Any help you might have would be much appreciated- thanks so much.

Suz...