iT MISFIRES LOW rpm AND UPON ACCELERATION, changed TPS and Heat sensor. Tested map OK, NOx is over limit. no over heating problem, no stalling issues. If cats were plugged top end would be ******* my guess. I'm stumped. Put new plugs in as well and checked injectors, new high octane gas. ( Aug 29th just figured it out), HEAD GASKET causing misfire #3, compression at 50 psi, so if you have a misfire CHECK FOR ANY AIR LEAKS FIRST, then coils and injectors, then compression test. Normal psi is 120 psi or above, IF (psi is low) Before pulling heads check rockers and make sure they are functioning correctly, if they are you must PULL THE HEAD. Antifreeze is not always present with a blown head gasket and codes may not show. Tricky stuff but I hope if someone has a similar situation this helps.