not shifting????

I have a 2002 Grand Prix just doesn't seem to be shifting right. When out on the highway and you go to pass a vehicle or just "punch" it down the rpm's will shoot up but it will not shift any ideas will greatly be appreciated

How many miles and when was the last tranny service?

77,000 miles and replaced filter and fluid at 65,000

Was that a pan drop service or any type of flush? Even though you may not have a SES/CEL light get it scanned with a trans capable scanner and see if any DTCs are stored in history. A few do not give a SES/CEL light. On the engine side check the throttle position sensor (TPS). Input and output. Input is PCM 5 volt dc reference and output is a dc voltage that will vary with accelerator position. Around .4 volts at idle to around 4.5 at WOT. Linear and progressive voltage in between.

Also, since you have a 2002 model you may consider getting the CAT converter checked out. See link below.

Click here (http://www.automotiveforums.com/vbulletin/showthread.php?t=681283)

Plus it would help to post your GP model and/or engine.

Grand prix GT 3.8 seriesII engine