1hotls1

iTrader: (6)

I'm fresh out of ideas on fixing this condition at wot. When the car starts backfiring, sometimes the tach falls to zero and stays there even though the car is running,sometimes it will backfire and die, but if I let off slightly it clears up. If this is a valve train problem, is it most likely a rocker arm or could this be a lifter? I've had the heads and cam about a year and have never adjusted the rocker arms, should I have checked them or is this a fluke problem? My track times have been slowing in virtually identical conditions over the past few months before the condition developed. Is this an indication of a problem? Help!