I have somewhat of a problem. I have an 01 Civic with the D17 that I run dirt track with. I blew a head gasket a couple weeks ago and had a guy install a new one. Now just shy of 4000 RPM the car will backfire and shut off. No check engine light. I can stop, restart the car and it runs fine again until 3500-4000 rpm in which case it will happen again. The car has an aftermarket cam, ADJUSTABLE cam gear and is equipped with hondata. I took it to my hondata dyno guy and I don't know whether he didn't try or honestly couldn't find the problem but that was unsuccessful. Just looking for some opinions before I go throwing parts at it. Thanks in advance!