auto trans. is constantly shifting?

i have a 96 cavalier with a 99 2.2 sunfire ecotec-and when im moving at a constant-the transmition acts like it cant choose the right gear-its a 4 speed with overdrive, and it will switch from 2 to 3-back and forth for like 5-10 seconds-how do i fix this? :disappoin it only does this when im done accelerating, and going at a constant speed- and mb-the guy i thought the guy i bought it from said it was an ecotec, i prob just thought i heard that at some point-and it didnt start doing this till about 2 months ago-ive had the car for 6 months.

Does it do this at any certain speed or just in general it does this? Maybe ur going just the right speed/rpms for it to not know what gear to go into. Is your tranny fluid clean and full? Does it do this when u accelerate hard or floor it?

Too bad GM didnt make an ecotec in 99.

Has it done it since the engine swap? I would say you have the wrong ECM/flash programming for the combination.Your 2.2 wouldnt be an ecotec....those werent in J cars until around 2003,2004.The Eco was standard on the new (then) Saturn ION,and was phased into the J car line dropping the old OHV "Junkyard" 2.2 in anticipation of the Eco-only Cobalt.

The ecotec motor was put out in the second half of the production life of the 02's.