I have two fault codes . . first one is PO 304 and the second is PO 304pd. I know that 304 is missfire on cylinder 4 but what is the "pd" after the second code mean? Thanks

 

the pd stands for pending...which means the computer doesnt know if its a solid code or not...AKA it only misfires once and awhile...

hope this helps.

if it was a straight 304...chances are that cylinder isnt firing AT ALL.

also if you don't already know what it is..check your plug wires(for cuts and nicks)...(if its a 4.6) and if its a 5.4 then check your COP's(Coil On Plug)...if i remember correctly the cylinder 4 COP is famous for getting wet from the antifreeze hose dripping on it...chances are you will need to replace it.

THNX
Duggy

 

its a 4.6 155,000 miles and has original plugs and wires. pulled a plug found the gap about 125 should be 52/56 guess that be it. also found dripping antifreeze. BIG thanks for the response . . . off to the auto parts today.

 

goodluck!....also with that many miles...i would recommend changing all plugs and putting a full wire set on...i just did mine..and man it made a difference.

also while you are in there and have your air filter off...you can take out your MAF(Mass Air Flow) sensor and give it a cleaning...that will help your idle and overall performance out a bit....just pick up a can of Electric Contact Cleaner or SensorKLEEN...at your auto parts store...and then follow these steps....clean-maf-mass-airflow-sensor.php

THNX
Duggy