today i went to gst motorsports in union city, ca and was scheduled for a basic dyno tune reflash. i have just TBE on my 2003 evo. they began the dyno tune and the tuner found that there was some knock. he said it could have been the downpipe hitting something or the exhaust moving around. i thought it was the shi**y 91 from chevron and bad spark plugs. all in all he didnt get around to tuning it due to the knock and seemed to kind of put it off until later when i had to go to work he called me in. anyways i wasnt too happy with the service because i think they could have found the problem sooner. anyways anyone with experience please let me know what you suspect it is.

any helpful advice is appreciated.

 

Well to rule out your downpipe hitting the cross member...get some spacers down there. Be it washers or a nut, but make sure you have some clearance. Next time you go for a dyno session, make sure you get the best gas you can.

 

well yea but what else are the possibilities?

 

bad plugs, improperly gapped plugs, bad gas(my car ran like crap on Chevron), downpipe rubbing these are the most common reasons