I first did the EVAP reroute and then I replaced the valve cover. Neither of those fixed my issue as they have for some. Then I decided to do a valve job and discovered 14 of 16 bad valve stem guides so I replaced all 16...all 16 valve stem seals were hard and loose and were replaced...the #4 piston's 2nd compression ring was stuck in its groove and the piston was replaced because we couldn't get a new ring into the compressed groove...and the rod bearings were replaced for kicks. No more smoke.