02 chevy cavalier 2.2 sluggish

my chev cavalier has a 2.2 ecotech

a month ago the yellow service icon lit up but i could not find the problem and the car seemed to be running fine. 2 weeks ago the car seemed sluggish and gear changes were rough.(automatic) the engine seemed fine until it got up to 25-30 rpms but had trouble on hills. Now it can only get to 2000 rpms and cannot get high enough for the next gear.

I changed the fuel filter and the service light is now off, but still no power. Anyone been through this? Thanx