04 2500 6.0 check engine light flashing when on gas , i did my fuel pump, maf sensor , spark plugs and wires, a full oil change and have never let the truck get under a quarter tank the engine has around 160k and tranny got around 60k, when i start her she’s really loud, doesnt have much power, and check engine light flashes when on gas,with a terrible fuel smell in the cab, i have an after market exaust with only 2 o2 sensors and no cats and figured it could be that, i don’t know how to trick the truck into thinking i have the sensors in and i have a small gap between my flange and header that’s like 1cm i wasn’t sure if that could have anything to do with it.. not to mention it was running decent for a couple days after clearing codes and beating her up and down the street, please help…thank you!

 

Your poor computer is going nuts with all the mods, the gap isd making all the noise and flashing cel's always means a misfire. You need a code reader and a professional tune

 

deleting rear 02 won't cause a misfire. the gap will cause the 02 sensor reading to lean out...fix it then get then get the codes read...ask them to monitor the misfire counters...they can tell you which cylinder is misfiring.