The engine randomly revs up really high but the RPM’s do not move. It revs so high we shut the engine off as soon as it does this. It usually only does it while in park but it has on occasion done it while sitting at a red light or waiting in line.
You need to get it into your mechanic ASAP. What if it did this when you did not have your foot on the brake?
I am surprised your CEL is not illuminated. But since the tach does not show the RPM increase, your ECM might be failing and in turn not turning on your CEL.
I will definitely do that, thank you so much!
Definetly something off there . If the engine is actually reving the RPM’s has to go up . Hard to speculate what that might be .
I suspect a bad body control module. It would not only cause surging but an incorrect signal to the tachometer.
Abnormal sounds from the engine compartment can give the impression that the engine is malfunctioning for example a noisy radiator fan motor or a failing air injection pump.
I doubt the body computer can take control of the throttle body and cause the engine to race, too many body computers being replaced here.