Please Help

I just bought a 96 Eclipse RS. Not sure what the technical name for the engine is but it is a 2.0L Dual overhead cam. Heres my problem. I got my oil changed yesterday morning. On my way to work it ran great. When I got out of work I made about half way home when I made a right hand turn. When I shifted into 2nd gear (5sp) the CEL came on and was flashing and it almost felt like it was slipping in and out of gear, but the RPM's did not change. I pulled over and checked all belts including timing. All was good. I let it idle for a while with no problems. it revs smooth and comes down smooth. It only seems to bog out when I am accelerating or keeping a constant speed. If I accelerate above 3200 RPM's the CEL flashes. If I let of the peddle and let the engine slow me down, no problems, when I brake no problems, when I idle, no problems, only when I accelerate or keep a constant speed. What could the problem be?
Please help.

It may be your maf sensor went bad. which my bro had a similar thing happen to him but it was a nissan sr20de it would ram to about 3500 rpm but would not go higher.try that out if its not sorry i cant help

Actually I fixed it the other day. All it was was a missfire. It didn't really feel like a missfire but I got the missfire code. Changed the spark plugs and she runs great again.