New plugs/coils - still misfiring

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RJGill84

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Just installed new NGK Iridium IX plugs and BWD coils today and the engine is still misfiring pretty badly. Any ideas or suggestions?

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RJGill84 said:
Just installed new NGK Iridium IX plugs and BWD coils today and the engine is still misfiring pretty badly. Any ideas or suggestions?

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Are the plugs gaped correctly? Are the coils LS specific or are they the Mustang coils (which need the leads reversed)?
 
RJGill84 said:
Gapped to .44 and they're LS specific

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So they are not correctly gap'd. That's just outside of spec, on the wrong side of the spec.
The spec is 1.0 to 1.1 mm (0.039 to 0.043"). Since the LS coils fail due to high voltage breakdown of the epoxy inside, it's better to start at the low end of the spec, 1.0mm (0.039"). This may not be all of your problem, but it is an issue. Using BWD coils may be another part of the problem.

What are the exact five character OBD codes that you are getting?
 
I wouldn't classify it as a "bad" miss - just kind of a shimmy/shake at idle. I regapped the plugs and it didn't really make a difference, still a slight shake at idle.

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Make sure the connectors are firmly attached to the coils. They should click when attached.
 
RJGill84 said:
No codes at all. Replaced all 8 coils and plugs.

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Is it better/worse/same as before you did the work? Try swapping one coil pack at a time with your old ones, and start the engine each time you replace with your old ones and see if it goes away. Could be one Coil is a bad batch. But at least we can narrow down which cylinder has the misfire.
 
BigBalla39213 said:
First off to my knowledge..... An Iridium Plug gap shouldn't be Deviated.
Click to expand...

What it is, is you shouldn't regap an iridium plug by forcing the gapper in. You have to use a gapping tool because if you slide the gapper tool in you can damage that very skinny center element. If you don't have a gapping tool, a fair sized screwdriver will work. You pry against the ground lead very carefully using the base ring the grounding element is attached to, and you pry a tiny bit on one side then the other to make sure to not pry the ground at an angle. A very delicate touch is required, but the center element is never touched doing it this way. To measure, you can still use a slide gapper but you just lay it against the ground strap vs center element, you don't force it in. If it takes any pressure at all to get it in, you're still too narrow. Ideally, you will feel a an almost imperceptible bit of slide friction but no pressure against your fingers as the gapper passes through.
 
Yep, having the same problem. Seems like, other than at idle, it happens when accelerating in the low band of 4th gear. I've changed plugs and tested coil packs. This was not brought on by a valve cover gasket failure. It just gradually materialized and has progressively gotten more noticeable.
Could this be a fuel delivery issue?
Edit: Not throwing any codes.
 
Thicktoast said:
... and tested coil packs. ...
Click to expand...

They are COPs (Coil-On-Plug), not coil packs.
How did you test them? A resistance test of the coils is useless. The most common coil problem on the LS is that they become marginal because the firing voltage/current becomes low due to internal high-voltage breakdown. The only way to test for this is to scope the coils during a stress test. It's cheaper to just replace all of them.

http://www.richporter.com/media/tsb-05-22-8.pdf


Thicktoast said:
.... It just gradually materialized and has progressively gotten more noticeable. ...Edit: Not throwing any codes.
Click to expand...

Classic marginal COP symptoms.
 
Are you sure its a misfire? Maybe there's a vacuum leak? Check your vacuum lines, check the MAF, air filter, intake, etc. How's that fuel filter look?
 
jjcool00 said:
Are you sure its a misfire? Maybe there's a vacuum leak? ...
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It could be both. Vacuum leaks cause rough running by causing misfires. The misfire would be caused by the mixture being too lean due to the added (and unaccounted for) air, but in the end, it is still a misfire.
 
Thicktoast said:
...Should I replace the fuel filter? +130,000 miles... If so, where in the hell is that thang!?
Click to expand...

Yes, you should. I have been surprised by how much dirt drains out of the filter when you remove it.
It's at the back of the wheel well for the front driver's wheel. Turn the steering to the left and remove the splash guard behind the tire. You'll need a Ford fuel line disconnect tool.
 
Thicktoast said:
A ford fuel line disconnect tool, eh...
http://www.youtube.com/watch?v=hkZRSMGqQ0E
Click to expand...

On at least one of mine, one of the connections didn't have the metal clip. Instead it was the type with the plastic push in clip. You can carefully pull that clip out (or break it and replace it), but for me using the tool was simple enough (yes, it does work on those connections too).

Either way, I'm sure you'll work it out.
 
Feck those clips! But a very small flat blade screw driver to help guide the clips made it easy. Man, the tank side of that old fuel filter was black. Thanks for the help.
 
Fuel filter, fuel filter, fuel filter! She now performs like she did when I first laid eyes on her! That girl was thirsty and my dumba$$ was making her drink through a pin hole.
 
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