Thanks rodeo02 and drw1000 for your responses. I really appreciate it. I have already been out over $1000 on repairs so I am trying to make sure what NEEDS to be done gets done. I did get a little more information after speaking with the mechanic...the P0316 code was cleared after the ignition wire set was replaced. Engine light is back on and the vehicle history is showing codes 171 & 174 system running to lean....what should I do next (least expensive method)? Mechanic wants to replace platinum spark plugs and fuel injection filter and do a 3-step fuel system cleaning, is this necessary?