Cylinder 6, new sparks & coils. Still misfiring!!

[JDeez100]

I'm driving a 2007 Eddie Bauer with 414,000 miles on it. It has been a company car with regular maintenance and mostly interstate use. It's really in great shape for the miles.

So it started missing really badly and I went and got the code checked at o'riellys. Cylinder 8 misfire and both banks running lean. So I went ahead and changed all the plugs. Then, the engine starting misfireing worse! It happens mostly when I'm accelerating, it shudders and I have to lay on the pedal to shift down a gear before it will getyup. A friend showed me his personally owed obd2 scanner, which I liked the idea, so I went and bought one too. So I checked the code and now it is cylinder 6 and only bank 2 is running lean. I moved the coils around, and the problem didn't follow. It stayed on cylinder 6. I went ahead and changed out all of the coils with new ones, and( as you could have guessed) still misfires in cylinder 6.(not that I really expected a change). I listened to the fuel injector with a screw driver, and it's definitely working. The only thing is it could be clogged up. Do I have any other options before I need to swap injectors or just clean them all with carb cleaner? Could it be anything else?

Thanks guys!!

 

[PotatoExplorer]

Hey, just wondering, did you check the wires leading up to the ignition coils? I've heard of them getting brittle and cracking, or even melting together.

 

[JDeez100]

Thanks for the reply Potatoe! No, I haven't done that yet. Frankly I kinda scared to because I don't want to have to get inside the wire casing. Seems like it would be a real pain. Is there a good way to do this?

 

[PotatoExplorer]

Oh no, nothing involved like that.

It's just those thin little gauge wires that run into your ignition coils. On my 2008, on either side of your intake manifold is some taped up/bundled wires that run from the back of the engine towards the front, then these wires further split off to the top of each ignition coil. When they split off from the taped up/bundle of wires, they split off into 2 thinly gauged wires and then to a clip (running into the ignition coil which is on top of each one of your plugs/cylinders). These 2 thin gauge wires are exposed to the elements in the engine bay and can get brittle, break, melt, etc... You can just check them without pulling anything apart.

 

[JDeez100]

What's the best way to check them? I have a multimeter, would that work? And would I need the wiring diagram?

 

[Bill MacLeod]

Pull #6 plug and inspect it. Could be faulty. What brand?
Do you still have any of the old plugs? Maybe swap one.
Use dielectric silicone grease on both ends of the cop.
Any codes stored?

 

[JDeez100]

Bill, thanks for your reply! Right now the only code I have p0306, but I have been having a bank 2 lean code a few times. That's why I was thinking the spark was firing, but the injector was clogged a little. I do still have the old plugs, and can try one tonight.

 

[JDeez100]

Pull #6 plug and inspect it. Could be faulty. What brand?
Do you still have any of the old plugs? Maybe swap one.
Use dielectric silicone grease on both ends of the cop.
Any codes stored?

And it's a master craft brand.

 

[PotatoExplorer]

What's the best way to check them? I have a multimeter, would that work? And would I need the wiring diagram?

I was just saying to visually check them. I had watched a YouTube video where this persons wires were literally melted together. Just make sure there's no cuts/cracks to the insulation of the wires leading up to the COPs.

 

[Bill MacLeod]

And it's a master craft brand.

Never heard of Master Craft plug. Best would be oem Motorcraft or Autolite HT1.

I had a bad experience with the Champion 1 piece.

 

[JDeez100]

Never heard of Master Craft plug. Best would be oem Motorcraft or Autolite HT1.

I had a bad experience with the Champion 1 piece.

Motorcraft, That's what they were. My bad.

 

[Laserbait]

Just to clarify, the coil that you bought is a DG511 not a DG508, right? I've seen a number of places show both for the 4.6l 3V.

 

[JDeez100]

Just to clarify, the coil that you bought is a DG511 not a DG508, right? I've seen a number of places show both for the 4.6l 3V.

Yea they are. So I went home and did a COP spark check with a little tool from pep boys, the spark was good, just a little orange. I checked the some other plugs and they are all slightly orange as well. I pulled the plug, a motorcraft, and it had a good Spark as well. The only things I can think of is the camshaft position sensor is off, the cylinder Has a compression issue, or the fuel injector is clogged(its firing, as I listened to it).

I think I'm going to pull all the injectors and clean them all anyways. 414k miles and no new injectors.

If I do a compression test and it fails... what do I do? Is there any that I myself can do to clean the cylinder without removing the head?

Thanks for the help guys!

 

[Bill MacLeod]

Seafoam then remove plugs, clean and reinstall? Or have a Ford tech do an engine top end cleaning.

At 414k, wonder what a compression test or leakdown test would reveal?

Any chance of sludge in the top end?

Any service history on the trans?

 

[JDeez100]

Seafoam then remove plugs, clean and reinstall? Or have a Ford tech do an engine top end cleaning.

At 414k, wonder what a compression test or leakdown test would reveal?

Any chance of sludge in the top end?

Any service history on the trans?

Well I jut put in new plugs a couple days ago... surely they don't need cleaning. I'm thinking the same thing about the compression test. Not sure. And the transmission was rebuilt 55k ago. What does that matter?

 

[Bill MacLeod]

Cleaning plugs would be after doing a decarb with seafoam.
Many have mistaken trans/rpm surge with intermittent misfires or ignition related issues. Due a search and you will see.
All part of tossing around ideas.

 

[Blackexplorer06]

A compression test (wet and dry) would reveal if the cylinder is bad. In other words not sealing valves or leaking past rings. A burnt valve can cause a misfire. I had a bad valve on a Taurus that caused a misfire. A new valve and seat solved the problem.

 

[JDeez100]

How should I put the seafoam in? Straight in the gas tank or in a vacuum line?

 

[Bill MacLeod]

Slowly through a vac line into the upper intake?

Compression test first? (interested in the results if you do this)