Need Help! Code P0306. Already Had Plugs Replaced

[Adieu]

Injector #6

Costs 30-40 bucks, swappable in driveway in 5 minutes, all you need is a socket to loosen the fuel rail on that side (12mm probably? Maybe 10mm i forget) And gloves and paper towels cuz a little fuel will drip out

Take off fuel rail bolts on that side, unplug injector #6, pull up on fuel rail gently, click the injector out of the fuel rail, swap new one in, lower fuel rail and injectors back in, plug in new injector, bolt fuel rail back in.

Done.

 

[Transporter]

Have you had a bunch of rain lately or steam or pressure washed you engine (by the way NEVER do that with an engine with COPS)? Pull the COP off 6 and see if there is water, condensation, or moisture in the Boot. Did you use plenty of dielectric grease when you changed the COP?

Always shotgun Spark Plugs and COPs at the same time. That new plug could now be fouled/bad from running with a bad COP. Also make sure the plug is properly gaped. So you don't really know what is good or bad anymore. Next, the P0306 can be caused by more then just a bad plug or bad COP or both. Check to make sure you didn't pinch any wires shorting them to the engine block when you put everything back after changing the plug and COP.

Next, the cheapest way to buy COPS is off Ebay and Amazon by buying full sets. For me it is a little easier because I have the big V8 that takes the same COPs as the V10 so I buy the 10 pack for $42 (less then one COP from NAPA or PEP Boys). They are made by the same company that makes the Motorcraft OEM COPs. They last 60 to 90 thousand miles so who cares if they always make it to 90K when they cost a fifth of the expensive ones. Many times Ford Dealer COPs don't go 90K miles either and the cost over $125 each.

When buying online just determine which COP (DG508, DG511, etc) that your vehicle uses, then purchase the ones that match that.

I have had great luck with Deal and ECCPP COPs.
https://www.amazon.com/ECCPP-Compat...keywords=ignition+coils+for+ford+4.6l+5.4l+v8

I keep several pre-gaped plugs, COPs, tube of Permatex 22058 Dielectric Grease and the sockets to change them in the truck in one of those small plastic toolboxes from Harbor Freight. Speaking of Permatex, make sure you use plenty. And of course I always have either my OBD II handheld or bluetooth dongle with me for Codes.

 

[DanTheMan97]

Think I found the problem.... The first thing I did after swapping the coil pack was replace the fuel injector as Adieu suggested. Figured it was a simple thing, so why not. This did not help at all, but after some more research I did find out that the 2005's 5.4L had a recall awhile
back with the fuel injectors (posted pic below) on another forum. This often time led to the Catalytic converters being plugged. Might be worth reading about for those who own a 2005 like me. This freaked me out a bit for awhile as I thought my converters might be bad and I did not have that much money to spend right now. I thought I'd take Transporter's advice before I touched the converter and replace everything on that cylinder and since I just replaced the COP and Injector the only thing left was the plug. Come to find out the plug on cylinder 6 was loose by rougly 1/4 turn, so I pulled it out and it definitely had seen better days (posted pic below of old & new). I threw the new plug and the problem seems to be 99% gone. I'm hoping the plug being loose caused it to look like that and not the other way around. Not very happy with the shop that I payed to swap them......

 

[BlueStangGT]

Whoa! The U strap is burned off?

 

[DanTheMan97]

Whoa! The U strap is burned off?

Yep, completely gone. That plug had only seen about 7,500 miles at most

 

[Transporter]

Glad to here you are back up and running properly. Rarely when it comes to COPs and Plugs can you get away with changing just one and if you do have to come back troubleshooting it, plugs don't cost that much, change it again.

 

[1955moose]

Dan you might want to dig a little deeper, as your running too hot, that's why your plugs are melting down. Are you sure you put in right plugs/right heat range? If that's all correct, even though theirs no misfire, or lean codes, you need to find out why. It could be as simple as a clogged filter, or a weak fuel pump. Or something more complex. These sparkplugs are supposed to go 80k minimum, not 7k. Too hot, or preignition will destroy plugs everytime. Was your Suv pinging driving, especially on grades?

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[DanTheMan97]

Dan you might want to dig a little deeper, as your running too hot, that's why your plugs are melting down. Are you sure you put in right plugs/right heat range? If that's all correct, even though theirs no misfire, or lean codes, you need to find out why. It could be as simple as a clogged filter, or a weak fuel pump. Or something more complex. These sparkplugs are supposed to go 80k minimum, not 7k. Too hot, or preignition will destroy plugs everytime. Was your Suv pinging driving, especially on grades?

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I'm not sure what you mean by pinging, But it did seem to struggle more often while maintaining speed up hill. Also would be much much worse pulling my car hauler around; had very little power. I did replace my fuel filter this past winter, so that shouldn't be a problem.

I told O'Reilys make model etc, and they gave me the newer plug. I checked the plug number on the old and new plug to make sure they matched, so I'm 99% sure its the correct one. Could a hot plug cause it to become loose?

 

[Big White]

Yep, completely gone. That plug had only seen about 7,500 miles at most

You're assuming they actually changed the plug. Wouldn't be the first time someone paid for something and it didn't happen.

 

[1955moose]

Any mechanic worth his sockets checks a new spark plug against an old one coming out. You match thread length, porcelain projection length. As far as a spark plug coming loose due to a heat range too hot, the answers no. What usually causes a loose plug is a mechanic that doesn't know how to torque them down. When you stated the parts person at Oreillys gave you the newer plug, they gave you a one piece plug that won't break on removal like the original Ford one. Are you doing the repairs? Or a shop?

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