Thanks Flatrater - I am planning on having them take another look at it this week.
It is just very frustrating, since paying this car off in January I have invested about $2k into it.
I do know that this last time they were checking the wiring harness for breaks and that is when they found the bad ground wire.
As for the problem going away when it is put in park does not happen with my car, it just continues to race and sounds like it is going to blow up. Yikes!
If I turn the car off and turn it back on it will occassionally run normal but usually ends up racing again down the road.
So I will mention that vaccum leak, I believe that has been a problem in the past - the check engine light has been off and on for about 3 years. They told me that an emissions code kept showing up and that if I loosen the gas cap (or was it tighten?) it would go out on its own. So sometimes the light would go out and stay off for months or weeks and then pop on again for months or weeks. But this never caused any problems with how the car ran.
Thanks again for the info
Kris