OK so changed plugs NGK PFR6B,s and did the fuel filter started it up and it sounds rough when idling, once driving it smooths out, also it seems to be blowing more black smoke when cold (always did till warm) it is a forged motor with early link ecu. I've checked all lines, FMIC piping and I cannot see any problems I did a QUICK check of plug gaps but they seemed OK it also said not to adjust plug gap on box ?