2010 Silverado CrewCab 5.3 / 6-speed transmission. The problem started in May 2011, starrted running rough and then check engine, service stabilitrak lights came on. Dealer said had a number 7 cylinder misfire condition and fouled plug. Replaced plug and back in business. Oct 2011 began running rough again and check engine light came on. Dealer said had a misfire and replaced all the spark plugs. Nov 2011, oil level low light comes on, Dealer says there is a tech bulletin to add oil splash shields due to the AFM relief valve misdirecting oil and allowing oil to bypass rings and burn up. Bulletin completed and now beginning to run rough yet again. From a start it surges and sometimes after turning feels like the throttle goes flat. Gas pedal in the same position, just feels like lost power. Push the gas pedal a little furthur and tach jumps up and surges forward. I think it could be a plug issue again and am wondering if I should get a tuner to disable the AFM. Any ideas?