2008 honda fit sport. Engine cuts out at 4.3k consistently in 5th gear but i can make it to redline in 1st every time, 2nd sometimes but sometimes it cuts out at 5k, 3rd and 4th usually cut out somewhere around 4-5k. i get hard engine braking and no throttle response until the rpm drops significantly.

speedometer also goes from 0-140 from 0-5 mph and then gets stuck at 140 until about 30 then flips to 0. don’t know if they’re related.

also got a bad idle sometimes.
any ideas on what it could be other than ecu? that’s what i’m leaning towards right now

 

Need to pull codes and see what you get. The engine dropping rpm makes me think it's going into limp mode which shuts the throttle body and won't allow rpm above about 3,000. My guess is that it's going into limp mode due to an extreme lean or rich condition.