i have a 95 civic ex with an d15 ecu in it my engine is d16z6 vtec but my ecu is non vtec my car won't go past 6500 rpms what will go bad if i dont change the ecu asap?

 

Car will not go past 6500 rpms since the LX's probably have a 6500 rev limit. If the injectors are a different size (from EX to LX) then I am sure something will go wrong. Most likely you would be running lean, and burn up pistons if anything.

Just buy a P28 and don't drive the car until you do.