So I bought an 05 Screw 5.4 with 130k last August. Truck was great until about 2 weeks ago, I could feel a miss in the engine at low idle while in gear. It wasn't much, but it was there, a small bump I could feel in the floorboard at stop signs. I assumed I had bad gas or something. Well it didn't go away, but it didn't get worse, so I ignored it. Fast forward to last Sunday and I'm backing the truck up a slight incline, she almost dies from the miss. Now I'm concerned. So I get a couple of mechanically inclined guys to come check it out with me. With the hood up, in gear, you could hear it miss but you could also hear something else, it was hard to put my finger on but it sounded like a vacuum or exhaust leak. You'd rev it and both the miss and the sound would go away, I was told not to worry about it and continue along.

Well yesterday I decided that I'd change the spark plugs (ugg) and see if that helped the miss and while I was there I could check the passenger side exhaust manifold for the infamous leak that these trucks get. Driving to the parts store the miss starts to move up into cruising RPM range causing lurching and now my truck sounds like a VW bus with a crazy loud exhaust leak. I'm pissed, thinking that now I get to deal with who knows what kind of issue with a miss and a freaking manifold replacement... GRRR!!!!

In desperation, (I have not the proper tools, nor the patience to tackle stuck plugs and the exhaust manifold) I call the dealership and ask for a quote for replacing the plugs and repairing the manifold leak... after picking my jaw up off the floor I decide that I'd rather beat the hell out of myself and the truck in doing the work than to pay them $1000 to do it.

Emboldened by my new-found hatred of dealerships, I buy the parts I need, Motorcraft plugs and new COP boots, and try to hunt down an exhaust manifold gasket set. No one has one, so I say screw it, go home and begin the 6 hour journey that will become replacing 4 spark plugs.

Since I bought the truck used with almost 130k, I don't know what to expect with the plugs, I assumed that they would have had to have been changed at least once with those kind of miles on the truck, but maybe not and that's why the truck is missing so bad. So I start on the passenger side, since that's where the sound was coming from. I tear into the first plug, turn it 1/8th of a turn to spray the carb cleaner in the threads, but a funny thing happens, it breaks with almost no force and is now loose enough to turn by hand. I pull it out and see that someone has indeed recently replaced the plug and has goobered the threads with enough anti-seize to stop Titanic from corroding. But I thank my lucky stars that it had been changed and that it came out in one piece.

At this point, I wonder if I should just put it back in and stop since all of the plugs are likely just as new and I can recoup my $110 worth of tune-up supplies. With some sage advice from my mechanic-ish father, I decide to replace the plug and continue further down the rabbit hole. Plug number 2 on that bank is exactly the same, shiny like new and goobered.

Moving to plug number 3, I find something interesting. When placing the socket in the hole, I turn it with my hand to make sure I'm on the plug, but I don't encounter much resistance. Hmmm, methinks that perhaps they goobered too much anti-seize on this particular plug and it had worked its way out under compression, which would explain the exhaust leak. It takes me about 40 minutes to actually get this plug out of the well because I couldn't get anything to grab on it. When I do finally get it out with a length of fuel line, my heart drops as it comes out without the ground shield and, due to the quick onset of the problem, I didn't a Lisle tool on hand. I hop online, find some pictures of the tool to see what it does, find some instructions on making a tool out of all-thread, and after a trip to the hardware store we have the shield out. Funny thing about this plug is that it lacked the anti-seize that others had in abundance and appeared to be in much worse shape.

Darkness is quickly descending on me and I'm running out of time, so I decide that since I've got most of the junk out of the way (hoses, computer, brackets), I'll finish this side of the engine and call it a night. I get my wrench on the last spark plug and what do you know, it's stiff. The last one of the night and it's the only one acting like these things should. So I follow the TSB, back it out 1/8th of a turn, spray in some carb cleaner, and wait. After 15 minutes of waiting, I get a torque wrench, set it to 33 ft-lbs so I'll know when to stop turning and go to town. It acted like how everyone describes it should, screeching and moaning as it inched out. The only thing tighter than the clearance of the ground shield to the head was clenching of my butt cheeks because it was dark and this last plug would take far more time and effort to get out in pieces. Finally, after 10 minutes of turning and clenching, it comes out in one piece. Curiously, it also lacks anti-seize and is in considerably worse shape than the first two. Not caring a whole lot about that because time is short and I'm freezing at this point, I hook up the computer and battery, and then crank on the starter to blow some missing porcelain chunks out of the cylinder with the broken plug (these trucks will start on only one bank by the way). I put a thin film of anti-seize on the ground shield only and throw all of the plugs back in. 30 Minutes later, everything is plugged back in and ready to go. I fire it up and she runs like a dream, no more miss and no more exhaust leak.

Now, to the moral of the story. Despite only getting half the job done, I'm deeply satisfied. Not only are the problems gone, but I've gotten the harder half of the plugs done. But all is not well as I am left to ask the obvious question, why did this happen in the first place? The only thing I can think of is this: the truck comes from a sordid past. It was repossessed two years ago and spent that time bouncing from reseller to auction and back. During that time, or even right before I bought it, I wager that it wasn't running too great and the current owner/seller wanted it fixed for as cheap as possible. He takes it to a shop, they start on the passenger bank to replace the plugs, they take the low hanging fruit first and replace the two front plugs without issue. They then move to the third plug, try to pull it and it breaks, trying to avoid work and further costs, they simply re-tighten the plug and pretend like nothing happened. They then skip the last plug because it requires removing the computer and bracket, thus saving time and money while still being a-holes. After a couple of thousand miles from me, the plug works it way out and suddenly the truck begins missing and leaking exhaust out of the plug hole. It's that, or the shop really did replace this plug and goobered it with a ton of anti-seize which then caused the spark plug to back out and the leaking exhaust blew the remains of it off. Are you supposed to anti-seize the threads too? The TSB said only apply it to the ground shield.

Anyway, I just wanted to share my experience and possibly spare someone the frustration that I felt in thinking there was something seriously wrong with the engine on top of the exhaust manifold leaking. Oh and to add injury to insult, before starting the work, I was trying to demonstrate the miss by putting the truck in reverse, applying the park brake, and listening under the hood. Well I forgot to pop the hood, so I lean in halfway and accidentally pull the park brake release instead of the hood release. The truck lunges back and starts to roll into the street with me hanging halfway out of it, luckily I manage to get back in and apply the brakes but not before severely spraining my ankle. $%^#!ing vehicles, crap like this is exactly why I'm a network administrator and not a mechanic.

 

Wow, what a story. Hope you heal quickly.

As far as the exhaust manifold leak goes:

It is probably a small crack at #7. Gaskets wont fix it. I learned this from experience. Last fall, I purchased gaskets and started the task. Broke one stud - dang - could not extract it. Bolted things back up -- thought I would wait until I needed to do head work to get the stut out. Still have the leak. It seals itself up after about 15 seconds of warm up time.

 

Nice write up. Your father is a smart man. My thoughts are the same as yours. Change two plugs and stop because it's hard and costly. Have you change the other bank yet? Do you have an exhaust leak or was it the spark plug?

 

Though I have an 2004, 4.6, those plugs were really seated in there too. Alot of dust and debris down in the holes. I moved the plugs a bit, then vacuum out the hold. Did not want any dirt in the cylinders. It worked, and you do feel good afterwards that you could get er done.

 

Thanks guys. The exhaust leak was actually the broken plug, compression was blowing right by it, causing the miss and the "exhaust" leak sound. It does feel good to be done, but I still need to complete the other bank before I can feel great. As a side note, I believe that even before the miss developed, with two worn out but complete plugs on that bank, my off-the-line performance was very noticeably worse than it is now.

 

Well you have done the harder of the two sides so that is a positive. Based on what you have found I would not be surprised if the last plug on the drivers side has not been changed yet. Sounds like whoever did changed the easy ones and the stopped when one broke. And they did it just so they could get rid of the truck. Either the dealer so it would sell with no conditions or the former owner so the dealer wouldn't catch the issue.

Anyway sounds like you are on the right track and have figured out the problem just sad that someone would do this before parting ways with the truck.

 

Can to much anti seize cause it to back out? I may be having that issue then... perhaps.

 

If plugs are torqued to specs you shouldn't have a problem with the 5.4-3v engine plugs backing out.

 

Just thought I'd give you guys an update. I finished the driver's side plugs on Saturday. Just as I thought, all of the plugs were replaced on that side because they were easy to get to. Freaking lazy mechanics.

Anyway, I just wanted to report that out of the 6 plugs that were replaced by that shop, which were coated in anti-seize, all of them came out super easy. So there is hope that if you replace the plugs once, you'll be in better shape the next time around.