I had my 2002 CTD in the shop for a bad oil leak. I thought it was the front seal they said it was the rear timing case gasket and would have to pull the cam to fix it. They got the leak fixed and I had a Fluidampr installed by them,but the truck runs rough, backfires and smokes at 160 degrees when it gets to 190 degrees it runs fine. I've had it back to them 4 times they've replaced the MAP and intake air temp. sensor but know change. Could this be a timing issue I don't have any codes coming up so I 'am at a loss any ideas. would be a big help. thanks DEAN