Hi guys
I been having that problem for almost a month.
i did a manual swap with a used engine from manual fd with tranny.I did evrything and i left a auto wiring and the car runs great at idle but it won't let me rev past 4000rpm. Checked injectors and still nothing , but i think it might be wiring ?
any clues guys please help

 

It could be the crankangle sensor.

 

I had a car with a similar problem. The wiring was partially pulled out of one of the crank angle sensor connectors. It would rev nicely/smoothly to 4500 rpm then fall flat on it's face and would not rev past 4500 rpm. It would do this under load or in the driveway. It was hard to track down, the 4500rpm problem is typically a boost problem.

A new engine harness solved the problem!

 

did you clean the injectors recently? one could be stuck shut??

how did you check them? pull them out and put 12V to them and listen for a click...no click = stuck inj.

 

did you reset ecu? i once had a problem where it would not allow me to rev past about 4.5k rpm and would just cut out or backfire and i just reset the ecu and it was all good.