hmmm... prolly won't bother then trying to do it myself... I don't even know if that's the problem. I just got my valves adjusted at 192k, and the next day, it almost sounded like a stuck lifter on a gas engine when I rev it... then ithe tach seems to "grind" back down to 750 rpm, but I can still pull 6-8000 lbs and barely feel it, and the check engine light has never once come on... any idea what may be going on? does a bad injector(s) automatically make the check engine light come on?