i have a jcb 510-56 that will randomly run erratic. after it warms up the tach will freeze around 1500 rpms and the engine will start to miss. i have code p0371-00 and sometimes p0372-31. these are the only codes i can get from it. if you turn the key off and restart it it runs fine again for awhile. i have checked and cleaned all grounds on the machine and checked the connections to the ecu. i dont have access to these codes and was hoping someone could point me in the right direction.
Sounds like you got a Injection pump or wiring issue to the the pump and or a issue with crank sensor. First code is for optical sensor receiving bad/erratic data second is a code for timing data being off. Check engine wiring for rubs and the like. A bad crank or cam sensor might also be a culprit. Or a sensor going bad possibly a software issue. If it runs fine after a restart I would go with a sensor or software issue.
wiring to crank sensor was bad. replaced crank sensor and issue was solved. thank you