99 grand am se V6 - Computer Problems? I guess

[ouway]

My girlfriend baught a grand am from a pretty shady dealership -
1. ever since she got it the gas light has been stuck on full, occassionally it will go to empty and ding then go back to full.

2. as of the last week the temp gauge will randomly go all the way up (about 260), beep, then go back to about 220-230 with in a matter of seconds. I checked (with my hand) to see if the radiator or engine seemed hot - but it was still fairly cool.

3. yesterday the temperature stayed up for an extended amount of time then the trac off light came on and the car would hesitate esecially from a stop. After about a 5 minute rest the car started again with out the trac off light and drove fine for about another10 miles before we got home and haven't started it since

Am I having a computer problem or fuse problem, possibly a bad ground somewhere. What the hell is going on? Do I need a young priest and an old priest?

Please Help

Thanks

[shandy1994]

when i first got my 99 grand am back in 2000 the gas gauge did the same thing. Luckily it was still under waurantee so i was able to bring it right back to the dealership.
what mine would do is every time i filled the tank, as soon as i started going down the road with it, it would chime and the yellow (empty)warning light would come on and the gauge would drop down to empty.
I know it sounds crazy and it was quite a while ago but i want to say it had something to do with the gas tank cover. I know, quirky, but i am almost positive thats what it was. actually I know for sure thats what it was because i remember them also telling me that i should never open the gas tank when the car is running. I do think it has something to do with the computer in the car too though.
As far as the other gauges are concerned, the only time i had issues with the other gauges was right before the battery quit on me. All the gauges includeing the odometer started acting funny, then all the sudden one day it just didnt start. The battery was completely dead.
I put a new battery in it and never had that problem again.