May be due to low-idling caused by the engine build components. Cams are known to cause P0300 on the QR. I had the P0300 (multiple cylinder misfire) with my Nismo Cams, but bought the Cipher cable and raised my idle by 50RPM and the problem is completely gone. Nissan can also raise your RPMs, or anyone with a consult II for that matter-- most folks say you can get it done for $20-$40, but my local nissan dealership quoted me 1 hour of labor -- $149! I just bought the cable for $200.
I just read it was a "rebuilt" engine/not a "built" engine, so hmm...but maybe the idle raise might still work; I'm assuming they used stock internals? At a minimum, I would hook it up to a code reader and see what it's idling at, if it's low ~700-740RPM, I would have it raised to at least 750RPM (although mine is currently at 800)
04 Spec V
Nismo: Cams, Cat-back, FSB, RSB. JWT Valve Springs, BSR. AEM CAI, MMI, B&M SS, UR pulley, 2JR Plenum, Fidanza 11lb. flywheel, Spec Stage 2 clutch. BR coilovers, 6K swift springs, Nismo wheels, Projector HIDs @ 6K, LED tails and LED turn signals
~170WHP w Cats intact, CARB-legal.
Last edited by OrangeBeard; 10-20-2010 at 09:55 PM.