well the tune up consisting of new plugs seemed to solve a major vibration of the engine when AC was on .. badly worn out but clean plugs, nothing on them , just deteriated tip and bad gap ..everything seem to be showing clean, no carbon no nothing
now the new question is should I disconnect the battery and thus try to reset the computer which was trying to compensate for the worn out spark plugs .. and if so, how long to leave battery disconnected .. had tuneup done at Jeep
thanks for all the inputs !!