GoBig06
NAXJA Forum User
- Location
- SF Bay Area California
I have a 1999 4.0L xj that I currently replaced the catalytic converter and up/downstream O2 sensors. I was driving on the highway to get my cat hot for the emissions test and I got a P0300 random missfire code. I replaced all the spark plugs and wires then I tested the fuel pressure and got 44-45 PSI. Which is slightly low from the 49 PSI I should be getting. Is this a cause for concern or should I be chasing issues else where?