I have a 99 ex coupe with a 96 usdm b18c1 swapped in it and im running a obd-1 jdm p72 ecu. The problem is that occasionally when im running it hard the rev limit some times will hit at like 6800 rpms or around there, it just started doing this recently. If i cut the ignition off it goes away but every once in awhile it will do this and it doesnt stop until the car is cut off. Any help or info would greatly be appreciated.

 

I am not saying that this is definately it but... My hatch has an ex cluster and I tap out at 6750 out of nowhere it started tapping out at 6000 for no reason. some days yes some days no. I dug out my old monster tach and wired it up to the ecu and guess what. My cluster is off alot of the time. I would say about 95% of the time it is off by up to 1000 rpm sometimes 300 everyonce in a while it is dead on. The tach in my cluster is **** and yours COULD be starting to fade too. But like I said just a possibility.