Have a big mystery here and I am at a loss. My 06 6.0 has 190cc inj, turbo, egr delete, SCT custom tune and straight exhaust. I have developed a miss and or rough idle after the truck went in the shop for a flywheel replacement. It ONLY occurs when in park and at idle... if you put your foot on the brake or put it in drive or turn the AC on, it quits. It is as if you put the motor under a load it solves the issue. I am thinking electrical as in ICP sensor? It has a new FICM already and is not showing and codes. Any Ideas or thoughts??