Check engine light - P0303 Cylinder 3 Misfire Detected

Boulee · #1 05-02-2009, 08:18 PM

my check engine light come on. stopped at auto zone and dude-o hooked it up to his comp and it read two P0303 Cylinder 3 Misfire Detected codes.

I recently had the 60,000 mile mainenace done so plugs are new.

Any thoughts or opinions would be greatly appreciated.

2003 Doddge Dakota Quad-Cab 4x4 sport
4.7L V8, 545RFE 5-speed automatic.

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f0x672 · #2 05-02-2009, 09:29 PM

i would check out cylinder 3 spark plug if i were you

tamcnally · #3 05-02-2009, 10:47 PM

Quote:

Originally Posted by Boulee

my check engine light come on. stopped at auto zone and dude-o hooked it up to his comp and it read two P0303 Cylinder 3 Misfire Detected codes.

I recently had the 60,000 mile mainenace done so plugs are new.

Any thoughts or opinions would be greatly appreciated.

2003 Doddge Dakota Quad-Cab 4x4 sport
4.7L V8, 545RFE 5-speed automatic.

You might want to look into a new coil pack.

meaculpa3x · #4 07-08-2009, 11:48 PM

I've had a similar issue for months now only it's Cylinder #1. I've changed the coil, spark plug, run a few cans of "seafoam" through it, even swapped the #1 and #3 injectors to see if the code moved with the #1 injector to cylinder #3 and I get nothing but a Misfire on Cyl #1 code everytime. I can't figure it out, looked at a possible wiring harness issue but everything is so well taped, strapped and loomed it would ba an absolute nightmare to unwrap and follow the wires all the way back to the computer or wherever. Then there is always the computer. Think a bad computer could keep popping a code that isn't really an issue?

CULOSE · #5 10-20-2009, 09:55 PM

Did you get the problem fixed?

Any ideas for a cylinder 2 misfire. replaced plug,coil,tested compression, tested fuel pressure, checked for power at coil and injector (both have power), checked connections they were good, swapped plug and coil from cylinder 4 to make sure new parts were not bad. It stills comes up with code P302 cylinder #2 misfire. Thinking maybe a problem with the valve or broken spring. Still not sure if that would cause the misfire. Any help would be greatly appreciated.

meaculpa3x · #6 10-21-2009, 11:48 AM

Oddly enough my light has stayed off since this last post. I cleared it one final time and it hasn't been back. Maybe the seafoam finally got the fuel system cleared of any gunk, who knows. Keeping my fingers crossed

CULOSE · #7 10-27-2009, 04:41 PM

For anyone out there with the same problem I encountered. The #2 exhaust valve rocker arm fell off causing a misfire due to the exhaust not being able to escape the cylinder. The lifter was not callapsed so I am not sure why it happened. Put engine through its paces and it runs great now.

magnethead · #8 10-27-2009, 11:00 PM

Quote:

Originally Posted by CULOSE

For anyone out there with the same problem I encountered. The #2 exhaust valve rocker arm fell off causing a misfire due to the exhaust not being able to escape the cylinder. The lifter was not callapsed so I am not sure why it happened. Put engine through its paces and it runs great now.

That's a hell of an odd thing to have happen without having catostrophic failure..

CULOSE · #9 10-29-2009, 01:45 PM

The rocker arm just happen to fall in a spot that nothing else was hitting it in the valve train. Was real lucky it didnt get caught up and destroy anything.

meaculpa3x · #10 10-30-2009, 11:46 AM

Im thinking you had a different problem than me. Mine ran perfectly fine just a check engine light once a month or so saying "misfire on cyl. #1". I don't know how yours even ran?