Had problems with coolant & oil temp readings on EM2 a while back, with help from Tracy, found if I disconnected both fuel gauges from EM2 ( still have Vans needle gauges in panel )  temp readings would work perfectly.  I let things go with that  ( so we could fly ) until now with annual due a list of squawks was generated, int. op. of  #2 EGT was on the list, new sensor was purchased after testing & during replacement found wires of orig. sensor inside FACTORY heat-shrink reversed from sensor  #1, so reinstalled orig. sensor & test run yesterday evening, works perfectly also noted O2 sensor readings now are smoother, not jumping around  ( was thinking that was the norm ).   Will now try reconnecting fuel senders in a couple weeks  ( holidays ) & see if they cause temp reading problems again, am thinking this was my orig. problem causing the logic in EM2 to do silly things ( technical term ) because my Vans fuel gauges work perfectly.  David R. Cook    RV6A  Rotary ( grinnin even more now ) :-)  that is stupid I have never done that before!!!!!!!!!!!!  smileyface