Engine shuts off at 2000rpms on 1994 Ford F-350

I've tried the ford dealer and other mechanics and no one can fix it, it shuts after reaching 2000 rpms Help
This is on a 1994 ford f350 extended cab

Asked by for the 1994 Ford F-350
if your truck has a 7.5l engine it probably is the psom (programmable spedo odomiter module)senser it is the chip directly behind the speedo needle. the only way to get one is to go to a junk yard