what ive replaced so far:
spark plugs (champion oem)-fuel pressure regulator-air filter-oil change-oxygen sensor-map sensor-engine coolant temp sensor-ran berryman b12 chemtool fuel system cleaner-checked ccv valve for clog (clear)-replaced ALL vacuum hoses.
according to test results CAT is doing its job. as for the jeep its runs GREAT, no overheating at all, has power and has NO problems...
while changing spark plugs i noticed the combustion chambers were RELLY carboned up bad. using the berrymans b12 helped clear alot but theres still some in there. (currently running another tank of treatment for carbon-could be the suspect??) im absolutely at loss now.. i hoping the fuel treatment will help with carbon in combustion chambers and that it will help bring nox down.