Many Problems with grand prix

[Sleek 93 SE]

Well lately I've noticed a bunch of problems Im having with my car. It is getting horrible gas mileage, it idles rough, the speedometer is way off, it doesnt even have enough power to spin the tires anymore. My battery is really shitty and always goes dead and barely has power, im thinking this could be one of the problems, but is it possible that maybe my computer is shot? Any input is appreciated.

Thanks

[Regal_GS_1989]

could be a just a bad connection from/or a weak battery. If there is a bad connection, or weak battery, your alternator will be working alot harder to power the rest of the car, which puts more strain on the motor, plus the lack of voltage can cause computer glitches, which can cause all the problems that you listed.

[Grand Moff Joseph]

I'd switch to a new battery first, then re-diagnose your car. As far as the rough idle goes, check all of the vacuum lines.

[gp90se]

when was the last time your car was tuned up and the o2 changed. are the ground/positve cable wires corroded (sp?), is the battery any good. are you beating the piss outta the car? the speedo issues is a commen issue with GPs, gunna have 2 pull it out and resoder it

[Sleek 93 SE]

Thanks Guys, Ill try a new battery.

I'm sure it probably needs new plugs/wires/o2 sensor aswell. Its got 94k and I don't think they have ever been changed.

[OldSkoolGP]

When my speedo was ogin whacky on me one time, I found out it was due to an exposed power wire contacting bare metal. It had actually started welding itself to the body! Along with a new battery and alt. check, check your wiring, especially if you have put in a stereo or any extra electrical goodies. Can never be too careful.

[Guest Anonymous]

The analog (and digital) clusters for our cars are alwasy very innacurate. Unless you have a prefect one to replace it with or have HUD, i wouldnt worry about it. I always went by my HUD when i had the analog dash.