I'm trying to get schooled before I tackle repairing my 5.4L (engine VIN code "L") '04 Expedition XLT (build date 12/03) with 91,000 miles on it.

It threw a P0306 Cylinder 6 Misfire Detected and a P0113 Intake Air Temperature Circuit High Input code and the CEL light came on.

I cleared the codes and replaced the IAT sensor but the hesitating and stumbling problem remained.

I found coolant pooled in the plug well around the #6 plug. Cleaned out the plug well and the COP boot then reassembled but the problem remained.

Now I'm preparing to change all 8 COPs and plugs. I've been reading posts here for days and at various points over the course of my study I been convinced that:

I have 2V heads,
I have 3V heads,
the heads are subject to plug blow-out,
the heads are less subject to plug blow-out,
changing spark plugs would be tedious but manageable,
changing spark plugs would be a nightmare (broken plugs requiring special extraction tools),
I need to replace the intake manifold gasket,
I need to replace the intake manifold also,
I don't need to replace either of them because it's a leaky heater hose,
... and the list goes on.

HELP! I know this engine has some issues but some years/configurations have less issues than others. Anybody want to pull out their crystal ball and predict what I'll be facing? At the very least, give me a definitive read on which heads/threads/plugs I'm looking at?

I have another post about the COP/plug change waiting for moderator approval (too many included links?) over in the "5.4 Misses" thread but it has fewer details in it.

All assistance much appreciated, thanks in advance!

 

Greetings BF,
#1. In an '04 EXPEDITION you have a 2V 5.4, NOT 3V. (2V 5.4L should have black composite valve covers) the 3V should have cast aluminum valve covers. There is another thread here in which I just recently mis-identified the '03-up Expedition as having the 3V engine which the F-150 NB got in '04. I was wrong!
#2. The plugs SHOULDN'T be subject to plug blow out, but in that thread it was noted that there are still quite a few with the '03 up 5.4 2V that SHOULD have the deeper threads that still have blow out problems. BE SURE to torque to MORE than Ford's recommended 14 lbs.
#3. Plug change shouldn't be that bad, shouldn't be any breakage problem like the 3V.
#4. It's PROBABLY a leaky heater hose, but I would do a pressure test on it (if necessary) with it warmed up. It should reveal the leak if it's the heater hose.
#5. I won't attempt to answer the manifold/gasket Q. Jbrew could probably answer that as well as any, and better than most.
All in all, I don't think it should be that bad. I had a '99 F-150 with the 5.4 2V but didn't have it long enough to need any work.

 

I'll just add to code58's reply, it's good/correct info. -

Your not the only one that gets confused about that one lol. Also, there's been other small differences under the expy's hood, compared to the 150's over the years. The PATS systems are different as well with the early models.
The 2004 should have 8 thread plug chambers. Torque Spec per Ford for the 2004 Expy =



Even still, 28' lbs is a safer spec. Residual carbon build up on old plug threads can spread the threads in an aluminum head enough to add to an already known problem due to the lack of chamber threads (only 4) in earlier models.

Other info: Here's the casting #'s & date for the 8 thread plug chamber revision -



Yea, but he's got coolant in the #6 chamber. That's unusual, I'll explain below.
If you have coolant in #6 it can only be from, -
a.) Top hose, -unlikely but possible under pressure and @ the clamp.
b.) Stat o'ring, - again unlikely.
c.) The pump, - very unlikely, they spew or trickle out a leach hole when bad. They don't spray.
d.) Heater Core Hardline @ the water pump stem. One or both o'rings may rupture causing coolant spray under pressure and intermittently.
e.) Intake Manifold Gasket, - Most likely IMO. The V8's are notorious for blowing the gasket @ the front water jackets. Being that the engine is higher at the front, coolant runs down hill with gravity and dumps into #6.

__________________________________________________ ___________

So your PO113 DTC never came back correct ?

Your most likely going to need a new coil for #6 once you've fixed the coolant problem. Coils should be greased properly before install.

There's currently another thread going with a user here that I'm helping. He's replacing plugs and gaskets from the intake manifold up. You have 91,000 miles, -so it may be a good idea to do the same. -Specially if the problem is indeed the intake gasket. Here's that thread -

https://www.f150online.com/forums/v8...questions.html

Let us know what you find and feel free to ask questions.

 

J comes through with flying colors, as usual!

 

Cool! THANKS!

Ordered a set of 10 DG508 COPs from Global ($100) by calling them direct.

I'll be getting 8 SP479 plugs from from rockauto.com ($18.48)

Which intake manifold gasket set should I get? The MS928361 for $25.99 or the MS98008T3 (PermaDry) for $59.79?

 

Yes he did. Your help was great as well!

Last night I decided to try an experiment while I wait for my new COPs and plugs.

I removed the COPS and plugs from #6 & #8 then thoroughly cleaned everything including the corroded secondary COP terminals. I re-gapped and re-installed the plugs (they were not in bad condition) after coating the ceramic with dielectric grease. Next I coated the COP boots (inside and out) with DG and re-installed the old COPs.

The hesitation and stumbling on acceleration is gone! Idle is smooth as silk. No signs of misfire remain!

I'm still going to do the tune-up after the parts arrive but the Expy is back on the road again and purring sweetly.

Thanks for everyone's help!

 

if the hesitation went away after coating the coil boot the dont worry about replacing the coils just get a new set of boots, and i agree w j its most likely the manifold gasket and would go w the permadry set i've replaced many sets of them and as long as you torque it down correctly u wont have a gasket leak again

 

I've never used the PermaDry, so I can't say. They look okay (HD), -it's my impression they're more for sealing abnormalities. There are one or two model years that the V8's have other known problems. These are with sealing on the passenger side toward the back. So, lol, yes, the manufacturer (Ford) put out a TSB and has special thickened gaskets for these model years, but you can only get these gaskets from Ford. They're the same blue ring gasket design, but they are allot thicker/heavier in order to solve the problem. The info is on this site and I've posted the model years and Part #'s around here somewhere. Maybe I'll look for them later if you can't locate them, but it's a good idea to check that out, I think you model falls into this category.

Like thumper posted above, torque that manifold down correctly. VERY IMPORTANT. I believe you do it three stages, but use four or five stages, the more the better lol. It's gotta torque down evenly and here, - you need a torque wrench. Borrow one from Auto Zone if you don't have one. This has to sequenced correctly as well. Has to be done, torque #'s are light, I believe there in inch lbs.

 

A heads up or one more thing to watch for. The Aluminum manifolds and heads can corrode and pit @ their mating surfaces, particularly around the gasket area. If this is the case, you need an aluminum filler prep first. It's not difficult to fix, the hardest part about it would be prepping the cavity for filler. That's done with a wire wheel or brush. Corrosion or electrolysis is common, more so with age.

I used a Permatex product (Aluminum filler) on the last repair that needed doing.

 

If the boots were damaged or deteriorating then I would agree. Actually, the boots were fine once I cleaned the conductive layer of dirt, grime, oil, grease, road salt, and coolant off of them. They were still pliable and looked almost shiny-new after I coated them with dielectric grease.

I think the only culprit here might be the manifold gasket. I think the misfire was nothing more than the spark finding that the path of least resistance to the head was through the coolant-soaked grime instead of the spark plug.

This makes me wonder how many COPs have been replaced unnecessarily when a good cleaning and some dielectric grease would have restored them to operation.

 

Doubtful, usually the windings will short. If they work at all after they're soaked, it's only for a short time. I give it 6 months max. The coils hurt regardless, shorted turns will add up over time.

 

Soaked? Where did that come from?

I pulled off the boots and spritzed them with some grease cutting household cleaner then wiped them dry before I greased them. I cleaned exterior surfaces of the COPS with the damp rag I used to dry the boots.

The only short was the high voltage pulse to the block through the 2-3 teaspoons of dirty coolant pooled around the plug at the end of the boot. If shorted coil windings caused the misfire, it would still be shorted and misfiring. In 40 years of working with electronics, I've never seen a shorted coil "get better".

In my experience, foreign materials like dirt, moisture and others generally interfere with the operation of advanced electronic and mechanical systems. Remove the interference and you restore the system to proper operation. It ran fine before coolant leaked into the plug well. Now the coolant is gone, the boot is greased properly and it runs fine again.

Doesn't mean I'm not still gonna do my maintenance a few thousand miles early , just means the pressure to get it running properly again is off.

Thanks again for your help.

 

...or did you mean soaked as in 'soak test' ( running a system at or slightly beyond it's maximum design limits for an extended period of time)?

 

Soaked =

 

Ah! I see. Well it was a shallow pool at best. Not even enough to cover the metal case or reach the ceramic insulator. I think there was just enough to create a path to ground but that was it. No visible leakage. No wet spots underneath and no measurable coolant loss.

Thanks again.