I have a sputter when starting from a dead stop. once boost kicks in there is no problem. On the highway at 75 mph, and the cruise control on I get a sputter. No loss is speed or rpm just a few sputters in a row. I put in new spark plugs gapped at .025, cleaned the MAF sensor, and ran seafoam through the intake, still sputters. Also have a cel for #4 cylinder misfire. Any ideas on what might be the problem?