I opened mine up yesterday and ever since i did about 30 min from opening it up, and gunning it thru a tunnel the check engine light comes on and eventually after drivin slowly w/ less noise it goes off?
could this cause the check engine light to come on?

 

It shouldn't, I never had a problem like that with my cutout. Maybe it is something to do with OBDII?

 

no problems here, it may be detecting false knock. get an LT4 knock module, i'm getting one soon just in case.