My motor is running pretty rough right now and I don't have a SES light. Is there a way to check it out w/o a scan tool? If not, would it be worth it to go to a dealership and let them diagnose it?

Thanks

 

if u got a M6 .. put it in 6th gear going slow .. then floor it .. if it goes smooth then ur optical part is ok .. if it starts bucking and farting .. then u need a new opti

or if u just rev it up high and it hesitates that can be a cap and rotor