AUTO MECHANIC PROBLEMS (AGAIN)

[Durian Fiend]

"A consistent misfire or sporadic?"  Consistent once it starts, apparently when its at operating temp.  I quit driving it when it started so I'm not 100% sure on the temp thing but it seems to be the case.

Crazy that wouldn't trigger something on the computer.

When I've had problems like this before I usually start by replacing the spark plugs and wires but I've never heard of coil packs before.  I know 2008 is an older vehicle but it's the latest model vehicle I've owned.

You could start with checking condition of the plugs. Coil packs and injectors are also good guesses.  With a Chevy, I wish you good luck!

Me, I'd take it to a trusted pro mechanic if you have one.