make sure you are not fighting harness rot. it started in calender 1992, i think, and continued until sometime in 95. the the engine harness and the throttle body itself can suffer from this. if the main harness is new, that doesn't mean all the little things that have harnesses attached to it were replaced also. just went through this on a client's 95 c220. he had the main harness replaced, i had to replace the throttle body, coil harness and the starter/trans harness. lotsa info here on the site, including the month of production the rotting stuff was installed when the car was built. good luck, chuck.