so i gave my 02 frontier its first tune up at 60K. mainly becuase the fluids and what nots have been in their for 6+ years and i want the truck to last me forever. The fluids were all black and needed to be changed, changed the fuel filter, repacked the front bearings and everything came out great and worked so much better. I changed the plugs, wires, cap, and rotor with O.E. recomended replacements becuase my truck was real hesitant and strained to do some pulling. The plugs were pretty burnt up. For about a 2 weeks they worked great and there was a huge difference threw out the power band. Now the truck is hesitant again and i can feel a vibration when it idles. I made sure the plugs are in and the wires are on properly. It has not thrown codes yet and I pulled the some of the plugs and they seem fine. Anyone have some ideas before I take it to the dealer and pay 11 million dollars for them to look at?