Replace 1 Coil Pack or all 8? P0303
08-08-2017, 09:20 AM
#1
Engine Misfire: Code P0303 - COPs - Oil in Plug Wells
Hey guys,
I was driving home last week and the truck started bucking. CEL light came on and threw a code P0303. I limped home and took it to the shop. They told me 6 of my CPs were bad and they wanted to replace all 8 and do a Fuel Injection Cleaning to get rid of the built up carbon.
I decided I would keep that $1200 and do it myself.
Should I start by just replacing the cylinder 3 CP? Or do all 8?
BTW, I put in new motorcraft plugs about 25k miles ago.
And is there a way I can do the fuel system clean?
Thank you everyone!
I was driving home last week and the truck started bucking. CEL light came on and threw a code P0303. I limped home and took it to the shop. They told me 6 of my CPs were bad and they wanted to replace all 8 and do a Fuel Injection Cleaning to get rid of the built up carbon.
I decided I would keep that $1200 and do it myself.
Should I start by just replacing the cylinder 3 CP? Or do all 8?
BTW, I put in new motorcraft plugs about 25k miles ago.
And is there a way I can do the fuel system clean?
Thank you everyone!
Last edited by SportsmanJake; 11-27-2017 at 05:18 PM.
08-08-2017, 09:58 AM
#2
Senior Member
I'd do all eight. Why? The other seven are most likely not far behind, and you can usually get a deal buying all eight together. Buy Motorcraft only as well.
As far as a fuel system cleaner, I personally like Berryman's B12 Chemtool. Just dump it in the tank.
As far as a fuel system cleaner, I personally like Berryman's B12 Chemtool. Just dump it in the tank.
08-08-2017, 10:59 AM
#3
Do all 8. Reduce your possible issues. If you only do one, and it continues to have issues, you'll have to do more anyway. Besides, as stated, the others may not be far behind.
BTW what usually causes them to go bad is gaps on spark plugs that are too big, requiring more power from the coil than what it is designed for. That is what happened to me, and what do you know, several of my plugs were gapping bigger and bigger. I would do the plugs as well. hell, you're already in there, and have the coils off, and most likely the fuel rails off. Use motorcraft plugs only.
I have heard from many to use only mortorcraft coils. i think that is good advice. I did not use motorcraft coils in mine though, and it runs great. But my truck is only a short trip 3-4 times a month weekend warrior. I bought a full set for $33.
BTW what usually causes them to go bad is gaps on spark plugs that are too big, requiring more power from the coil than what it is designed for. That is what happened to me, and what do you know, several of my plugs were gapping bigger and bigger. I would do the plugs as well. hell, you're already in there, and have the coils off, and most likely the fuel rails off. Use motorcraft plugs only.
I have heard from many to use only mortorcraft coils. i think that is good advice. I did not use motorcraft coils in mine though, and it runs great. But my truck is only a short trip 3-4 times a month weekend warrior. I bought a full set for $33.
08-08-2017, 12:55 PM
#7
Senior Member
Yes, the DG508 is the way to fly.
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08-08-2017, 01:25 PM
#8
How many miles on the COPs?
I would replace all the boots/springs first.
I have yet to have a coil go bad other than one that broke at the base of the connector.
Changed boots/springs 3 times at 50k and have 170k on the coils.
Use Denso 671-0001, $29.95 for 10 on ebay.
I would replace all the boots/springs first.
I have yet to have a coil go bad other than one that broke at the base of the connector.
Changed boots/springs 3 times at 50k and have 170k on the coils.
Use Denso 671-0001, $29.95 for 10 on ebay.
