Man, no clue what is going on but I just finished installing a motordyne iso thermal plenum spacer and stillen airbox and z tube. No obvious vacuum leaks that I see or hear. I did unplug the battery before I started, and tapped the brakes for a ecu reset before connecting the battery after install.

The first couple miles it was running fine then all of a sudden it won't Rev past 2250rpm. It's almost like it hits and starts bouncing off a Rev limiter. Here is a short video I made :



What could be causing this,has to be something I'm missing. Should I try an ecu reset the pedal method? It would have to be an ecu issue since in any gear it won't rev pst the exact same rpm?

Car is a 2003.5 sedan 5at

 

you def got an air leak somewhere..... check the intake again. i had this problem when i installed after market post MAF tubes

 

I agree with travlee, usually when something like that happens that indicates there is an air leak somewhere in your system. If not that try resetting the ECU and see what happens

 

Thanks, guys. Sorry should have updated the thread. I did eventually figure out the issue. And yeah, i guess that the car goes into limp mode and thats why it doesnt rev past 2250. But it was definitely an air leak. The cause was the stillen Z tube. It just isnt very hard plastic and when i would tighten down the hose clamps, it would flex and seemed like there was a constant leak. I sold it and got a OEM Z tube and no issues since.