My 2006 Pacifica started running very rough a couple of days ago and the engine light came on. The code reads P0304.

I had just changed the plugs two weeks ago (100,000 mile service) and was hoping that the new plug or the coil pack were bad. So, I pulled the #4 cylinder plug and it was gunked up very bad. I replaced the plug and put in a new coil pack in case it was not working.

After completing, I ran the car and within 5 minutes the same roughness was back. Pulled the coil pack and plug and the new plug was fouled badly. Looks like mud on the tip. This after only 5 minutes of driving. Also, i noticed the catalytic convertic was very hot, glowing in fact.

Can anyone point me in a direction? What should i try next?

Thank you for your time.

 

Do a compression test

 

Thank you. Can you explain what you think might be the problem and why a compression test is next? i just want to understand the thought process as i continue.

also, is this something i may be able to do? i am mechanically inclined. Do they sell the instruments at regular auto stores?

thanks for time!

 

Is there a way to manually clean the valves? I see that this engine has some history with problems with valve seats.
can the carbon buildup be cleaned up?

 

was this an issue b4 u replace the spark plugs ?

 

No Sir, not a problem prior to me changing the plugs.

 

then go back and check the plugs and coils and so on did u gap them did u use something other then champion?

 

I used Bosch Platinum's +4....so i did not have to gap them.

i did change the #4 plug and coil pack after i got the P0304 code and i had the same result after 5 mins of driving.

Did i pull a dumbsh**t with the plugs? Should i replace all plugs with Champion and try again?

Could this have caused the #4 cylinder to misfire?

thanks for your time.

 

I just went out and bought Champion Double Platinum's. I will install and see if things change. I will report back once this plug swap is done.

 

A pic of that spark plug you described earlier might help.