have you done anything to the timing to make it come off time? If not, then that prob isnt your prob. A car doesnt typically come off time for no reason. Maybe a vaccum leak, or faulty idle control valve/sensor (if your car is equipped with one).

I did my valves, if they arent perfect you can bend all your valve and say good bye to your head. I would adjust them...just get a ASE tech to do it or the dealer.