1999 Oldsmobile Intrigue RPM Revs up and down

While driving, I'm trying to increase speed a little bit when the engine would speed up slow down speed up slow down.. continuously until I either release the gas or push it harder. This is all while I'm keeping the gas pedal steady. The lower the gear the bigger the speed up or rev. It jerks the car continuously and sometimes when I let off the gas it will slam down into the lower gear. This problem is worse when going up hill mainly. This problem also exist even when I'm on cruse control. I thought maybe I needed Transaxal fluid but I checked it and it looks normal, but those can sometimes be tricky to read correctly.