I have replaced fuel pump, crank sensor, all plugs, wires, distributor cap, coil, fuel filter, cleaned injectors. I have blown 2 mufflers open. I keep getting loss of power, and intermittent misfiring of all 6 cylinders. I have had a new computer put in, reground all wires. What do I need to do next? I know I need a new catylitic converter, but replacing that will it stop my misfiring and backfiring to where it wont blow my muffler apart? The jeep will sputter at times, lose power but still run just wont do anything when i hit the gas pedal. Can someone help before i keep putting money into this old car.

 

Check compression, check fuel pressure. What codes are you having? And if the cat is broken a part inside, it can cause misfires. How many miles? is it random, or does the misfire happen all the time?

 

Also, if it is running rich (bad fuel milage, black smoke) it could be a front 02 sensor. The only last bout 100k. Sometimes they will through a check engine light, sometimes tehy wont. I once seen a dodge caravan, no check engine light, getting 2mpg as stated by the customer, was a bad o2 sensor (this was a extreme case)