Are we NO for ignition?

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blacktail

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Thank you GaryH. In that case, is it as simple as tightening the plug or is there going to be thread damage associated with the plug working loose like that?
 

whtbronco

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Should be as simple as snugging up the plug. I would just try to loosen each plug though, if one of them turns easy you found the loose one and you'll know right away if there's any thread damage. I can't say if there is or is not thread damage already.

Make sure you blow out the spark plug holes. Despite appearing to be sealed off by the coil boot, all kinda of sand and small gravel find their way in there. I also suggest some anti-sieze on the plug threads if you take them out or change them. The ratchet I posted a link to on page 1 of this thread is a must have for plugs in my opinion.
 
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blacktail

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So I spent some time taking a closer look at the exhaust manifold just now and believe I discovered the issue.

Not sure if you can see in the photo, but there is definitely black charring on the head but below the gasket. This really sticks out in person. All the head surface around this and driver’s side manifold are grey metal and clean.

Additionally, there is a bit of space between the nut and manifold surface on this one.

Haven’t touched the bolt yet to see if it spins because the CAT is so hot.

Is it possible that the bolt stretched but hasn’t broken? Not looking forward to tapping a broken bolt…
 

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SafariGoneWrong

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Very interesting. Causation versus correlation... The misfiring is real, shouldn't be happening but it's unclear the role it's playing. I'd be looking at changing plugs in the near future if you're not sure how many miles they've accrued. Manifolds...we know from many threads over the years the exhaust manifolds tend to warp, mostly the right side, but most folks complain of a ticking when cold. I replaced my right/passenger side 2 years ago when trying to determine the cause of my dinking sound and discovered the #4 flange had pulled away about 0.025" compared to the others that lined up with a straight edge. I noticed telltale black carbon around the gasket area so the manifold was replaced with Motorcraft. It hadn't started making noise though. The popping...could it be unburned fuel/air mixture being ignited outside the combustion chamber? I had major misfire issues in 2013 at 80K mi, engine under load, but never had a popping I can recall. Plugs were shot. Since you're up on ForScan Lite, I'd be looking at both cylinder banks and comparing what you're seeing for Long Term Fuel Trim, #2 O2 sensors in each catalytic converter and VCT Advance and Error. The bank with the offending misfiring cylinder (assuming it's only one cylinder) may show a lower, maybe even negative, Long Term Fuel Trim and higher converter O2 sensor voltage but since the misfiring seems to be infrequent, it may not substantially affect readings. And monitoring all things VCT out of OCD and paranoia.

If it's the passenger side manifold in your picture, you'll have to lift the engine to get decent access to the nuts/studs. I got a NAPA engine support bar (barely long enough) and followed the procedures in the Ford Service Manual. You'll need to loosen the left side engine mount through bolt nut, remove the right side mount nut, remove fenderwell splash shield, drop the sway bar, remove starter, remove alternator, loosen trans mount nuts along with disconnecting the exhaust down pipes from the manifold and any other bit that inhibits raising the engine...I recall lower and upper radiator hoses and fan shield had to come off.

It would be interesting if it were a combination of the most difficult spark plug to replace with the most common exhaust leak location on the 3V.
 
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blacktail

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safarigonewrong, appreciate your insight.

Here are the parameters I selected on Forscan lite. Please let me know if I’m missing anything.

At idle in these screenshots. Will reply with more photos since limited to 5 here.
 

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blacktail

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At 2000 rpm
 

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SafariGoneWrong

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Awesome! I don't normally monitor the upstream O2 sensors since they're always switching lean to rich. I've added alternator load monitoring, engine oil temp/EOT, trans temp, coolant temp/ECT, transmission gear selected, ignition timing (that's due to my former 2011 CR-V which had a factory built-in fault) and also the knock sensor counters. With these old engines I'm hoping to catch something prior to failure and looking for trends.
 
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blacktail

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Thanks for the suggestions!

I found this video from Ford Tech Makuloco that shows a procedure for removing the passenger side exhaust without lifting the engine. Not sure if it makes it simpler or more frustrating with tighter clearances.

 

SafariGoneWrong

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I watched that FordTechMakuloco video before doing my manifold job and thought it may be possible without lifting the engine; however, after removing the splash shield I didn't see a way to get to 3 or so of the lower manifold nuts/studs. Also, I don't know how much difference there is in the frame rails spacing between the Expedition and F-150. To my eye there's a bit more room in the F-150 but I have no first hand knowledge. I was also worried about one of the aft studs breaking and if it had to be drilled out, I wanted as much room as possible. I was lucky--no broken studs.
 
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