MY SPEEDOMETER JUMPS UP & DOWN WHILE ACCELERATING AND WHILE OFF THE GAS.. THE CAR KEEPS DOWN SHIFTING (I GUESS NOT KNOWING WHAT GEAR ITS IN) AND I AM NOT SURE WHAT IS CAUSING THIS. HAVE TRIED WITH THE SPEED SENSOR AND HUB SENSORS.. BECAUSE THE ABS AND TRAC CONTROL LIGHT KEPT COMING ON TOO..THOSE ARE OFF NOW BUT THE PROBLEM WITH DOWN SHIFTING AND JUMPING ARE STILL OCCURING.. ANY IDEAS?

any possible way it could also be a computer (electrical) problem??

Could be the part of the computer that communicates with the Gear Selector. The best thing to do is to find a scan tool that will show what gear the computer says the transmission is in, I know the Tech 2 will tell you, but not sure about any others. What could be happening is that the computer thinks you are selecting different gears and thus changing them for you. Try it at idle and also while driving, I would recomend having a friend in the car while driving to watch the tool so you can focus on driving, I almost him some little kids when I was playing around with my scan tool.

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2000 Pontiac Grand Prix GT

ALRIGHT. THANKS DO YOU KNOW OF LIKE ANYWHERE WHERE I COULD RENT OR BUY THIS TOOL FROM?

its really expensive, usually there are people on here that work at dealerships and they let you bring it in, other than that, most technical schools and any GM dealership will have one. To buy one is about 2 grand.

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2000 Pontiac Grand Prix GT

ours cost around 1300 used

we have a genieSYS II

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does it read tranny gear?

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2000 Pontiac Grand Prix GT

damn. don't have that much money to be dishin out.. maybe i can find a dealership or someone to let me borrow one. ha.

Check around on here for someone near you that has a scan tool that will read tranny gear, I will check mine tomorrow if you are in the chicagoland area.

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2000 Pontiac Grand Prix GT