Okay a few weeks ago my car died on me and wouldn't start back up. After trying EVERYTHING i finally got a replacement ecu. The car started up almost instantly. But ever since then the car has been acting weird. When I floor it the car only gets up to about 5500 rpms and shifts when it normally shifts at the redline. Also when it is in park and i rev the engine the rpm gauge doesnt stop it keeps going into the red. Could the ecu be junk? or does it need to be reflashed? I need help asap.

Is your car automatic or manual? Did you get a replacment ECU for the corresponding year of your vehicle? Also confirm if it was an ECU for a manual or automatic.

It was an ECU from another eclipse same year and automatic

The 1997 to 1999 dont have Ecu problems. I havent read about anyone having problems. You problem would be the tcu, "limp mode".

Try, pushing your tcu in on the tranny it could be loose.
Oh, I have an automatic and never redline it, only to 5500 when I'm coming off a highway on ramp.

You're risking blowing it up if you redline it all the time.

Thanks it only redlines in first and 2nd gear and Ill check the tcu