Are you getting a check engine light, even as it is not revving? Did you check for error codes in the ECU? It either has to be loosing fuel or spark. Does the tach hold at 3800 and follow the motor till it fires again? Or does the tach drop when it quits? If you have a bad crank or cam position sensor, it could be loosing it's signal at a certain rpm. Is the intake into the motor all stock? I had a home made intake on a fairly strong motor with a K&N element on the end, it turned out the 8 inch long piece of hose in the piping was collapsing shut acting just like the throttle was being slammed until the air flow dropped. I finally fiured it out with a vacuum gauge. It went to a very high vacuum when it should have had none. The last thing I can think of is the speed limiter is acting up. Is it 3800 rpm in any gear? If the VSS (vehicle speed sensor) line to the ECU is getting noise from the ignition, this may seem like the pulse rate for 149 mph where the ECU is programmed to cut the motor. It is a long shot, but a possible one.
Gary M.
Gary M.
