My buddy has a 08 with the 3.8 and it's misfiring bad while driving. Went on test drive before and after changing plugs and wires. Coil looks good no burn marks, so I doubt it's that. It's worst under load and physically shakes at about 35mph. Next thing I'm checking is compression and after that it's getting a fuel filter and injection cleaning. Any help in diagnosis is greatly appreciated for this is his daily driver and he's a pizza guy.