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K so i have googled and searched the forums to death. I had egr insufficient flow with misfire detected cyl 3. So i replaced the egr valve and the passage is almost completely blocked with carbon. About 3 cans of seafoam and 4 cans of carb/choke cleaner I am now at least getting flow through the egr ports. Which I am certain there was zero before. I keep getting misfire in cyl 3. All ignition coils, plugs have been replaced. I notice after I clean the egr ports the car runs great. But after 10 -15 minutes I am back to where I began. My only option is to remove the intake manifold , correct ?