what to do next I changed the sparkplug and the ignition coil, still misfires. on 2008 Chevrolet Silverado 1500

I am getting a "service stabilizer; service traction control" message so I thought a sensor was loose...I checked and couldn't see anything, diagnostics gives a p0306 code. Misfire 6 cylinder...sparkplug totally fouled and caked...still misfire, connect a new ignition coil...still misfires...what to do next?

Plug wire good? Also need compression reading!
1 more answer
agree with pushrod