Mr. Van Regenmorter

Slightly, it'll shake for about 1-3 seconds then turn off.

Ive got an 08 burb, LTZ, 5.3 4x4. When I go to turn it off, its been shaking. Kind of reminds me of an old 350 that's out of time. Ive replaced all plugs and wires and did the intake gasket, just in case there were any leaks. No cel. It did recently start doing this maybe a month or so ago.. I'm going on a 2k mile road trip in about 2 weeks and want to make sure I'm good before I go. TIA