Code 303 is #3 cylinder is missing. It's best to have a pro look at that as misfires are extremely hard to diagnose. YOu can check for a vacuum leak as that could cause it'. The other two deal with the egr not opening enough and or insufficient flow that cold be a plugged passageway a vacuum leak, and the egr stuck
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Thursday, May 18th, 2017 AT 11:35 AM