the wireharness is in like new condition,the connector ends are all shiny silver,the mercedes mechanic adjusted the air/fuel/after i replace the o2 and it still acts up,i will check into the coolant senser,keep in mind e verything is all original on this engine,the plugs/wires look great,i havent pulled the cap yet to look at the rotor,the wires and plugs are 21 yrs old,you think i should give her a fulll tune up next?i.e. plugs wires cap rotot? i did regap the plus and it helped a bit,but nothing to brag about.