Strange occurrences tonight. I changed my plugs and would you believe I actually had one new out of the box bad? Well this confused me a bunch, because I have never seen that. In the meantime Im testing everything. I would do something, get in the truck and start it up and rev the motor. It seemed to be missing at 3k rpms. In the midst of my testing I finally took it for a drive and it seemed fine and smooth above 3K rpms. (I had put one of the take off plugs back in). Im guessing I have never reved the motor to 3k in neutral before to notice this?

 

As far as the bad plug goes it does not happen often but I got one with a hair line crack not to long ago,,, just enough crack to cause problems,,, could hardly see it,,, rev limiters I know nothing about,, did not know they existed till I got on here LOL

 

As it's not nice to rev an engine without a load on it, there is a rev limiter built into the computer that'll begin to shut the fuel injectors down to limit rpm, so the engine won't come unraveled & make a mess if over sped with no load/at rest.