Check Engine light on, less power?
 

When my check engine light comes on (this happens about 50% of the time) it seems to be all boggy in second and third gear. When it’s off it seems to run fine. Any suggestions on what sensor could be causing this to happen?

Also, what is a good PSi to have the K03's running at? Right now they are stock and i have a stage 2 exhaust and front mounted intercooled system (engine barely reaches 60 degrees on a hot day). I do have it chipped and was wondering if the remapping of the ECU changes the PSi on the vehicle. Thanks for any comments guys.