well we think we found out mine, have you checked the timing by chance, i dont know how bad your miss is, but my timing is off cause i have a oil leak and its getting into my timing chain, from my gasket for the timing chain cover. also its making a mess with my opti, we are changing the opti, also my o2s are out of wack again, so its time to replace that again. well get back to you, changing water pump, opti, gasket, timing, and o2 sensors this weekend. well tell you how it goes.