This is my first post. I've been reading this forum looking for answers. I've gotta try to do this on my own. Ok here goes,
Check engine light came on code P0304. #4 cylinder misfiring. the plugs were changed. They were RED? My mechanic said he hasn't seen that before,
Light went off. Drove it about 20 miles(in the city) and the engine light came back on.
Same code P0304 #4 cylinder misfiring.
What should I do next.
Please help.....

 

what engine, what year, mileage. could be the coil or cap n rotor...

 

'01 quad cab 148,000 miles 6 cyl

 

I just fixed a #4 misfire code problem, changed out the spark plug wires. Problem went away.

 

I've been having the same problem... but mine went away after like 3days and hasnt came back on. I've been told plugs, wires, and might as well do the distrubutor cap and rotor.

maybe do a shot of fuel injector cleaner at your next fuel up.