electrical transmission problem

hey many some one can help me out with this problym ive been haveing with my 1997 grand prix gtp.

just recently my transmishion started to act up, sometimes it will feel like its sliping and other times it seems that its slaming the gears in. my speedomiter as well as the heads-up display also will drop down to zero when i engage the transmishion and will only display the wrong speed when its coasting. also my car will sparatically stall out while im driveing at slow speeds but will start right back up.

a friend of mine told me that it may be my speed controll sensor so i tried replaceing that, it all worked fine the first time i ran the car after changeing the sensor but once i parked and restarted it the problym returned.

the only mods that ive done to my car are tighter pullies, short ram intake, throttle body spacer, and a transmishion intercooler.

You dont need an external transmission cooler on this car unless you live where its very very hot or you pull trailers with it.

I would start by checking the speed sensor again and checking the wiring to it. Also could be a problem with your throttle position sensor, but I dont see how that would affect your heads up display.

They used to have a problem with the VSS connector contacting one of the power steering lines. The fix was just to bend the line out of the way.

you wouldnt happen to no if this car has 2 speed control sencors one in and one out, i thought it only had the one but a mechanic i was talking to mentioned that many pontiac cars had the two of them.
if so ware are they located