Could be compression loss due to sticking rings on 1 or more cylinders. Do you have tools to do a compression test? Do a cold, dry, morning compression test & see what your readings are, and if they're low, then do a wet test & see if they increase.
Originally Posted By: wsar10
Have you recently dis-connected your batt. ?
DO you have any stored codes (by key trick NOT scanner), IIRC the key trick works on the 2nd gen ZJ's. Either displays on odometer or the CEL blinks a specific number of times that dictates a DTC.