I was thinking to do some preventive maintenance so to speak, and replace all my injectors and coils, have already done the plugs.

I'm shopping from Rockauto, and I see they have several third party ones, and a "premium" ultrapower set and what not. Are there any real difference between these and the standard coils, and vs the OEM stock ones? Is the difference in performance or the lifetime of the coils?

 

If they are working, don't mess with them. I'm not sure that "preventative maintenance" is necessary.

If you want peace of mind, put a new cop or two in your trunk if it makes you feel better and carry your OBD ll tool. Injectors are pretty solid units.

Are there issues that make you think something's going bad?

 

Don't really have a problem with anything, but there's a minor problem that I'm not sure is related to the COPs. I do have a reoccurring misfire on cylinder 5 sometimes, but I think it's related to system too lean on that side, which makes me suspect the intake gasket on that cylinder, so gonna have that replaced. Also have intake runner manifold control stuck closed on bank 1, probably broken clips so I bought new ones which I'll replace at the same time. Will have Ford perform that job, bought the parts for less than half of the price Ford wanted here, but since it's Philippines their labor cost is really low so that's great. Though I could have done it myself, I just don't have the tools necessary to do it.

I heard that the injectors before a certain date, don't remember which, had a habit of getting stuck open and hydrolock the engine, something that would be really bad if it happened at speed. I think Ford had a TSB on that, and I'm not sure what date so I figured I'd just replace them all before I had that problem, and was thinking to buy OEM Motorcraft ones from Rockauto since they're actually the cheapest ones. Don't think it's worth paying more for a third party injector....

Replacing the COP's were just for my own "satisfaction" so I would know everything on that end was new and problem free. And was wondering if there's really any difference between the standard third party ones, the premium "performance" third party ones and the OEM stock ones. There's also some cheap third party ones, but I'm sure those have lower quality.

 

Admire your wanting to be one step ahead.
However, The COP's rarely go bad. The rubber boots and springs can go bad. The moisture with an intake manifold leak can rust out the springs and heat breaks down the rubber boots.
I've never heard of or seen a hydrolocked 4.6 or 5.4 engine due to bad injectors. Maybe search here for an example.
I'd look at the pcv elbow replacement, rear end seals, tranny flush, and ball joints before spending that cash.

 

Ok, thanks for the advise. I guess I'll settle for replacing the boots on the COPs and the O-rings on the injectors just to make sure it's all good. I'll also look into replacing the PCV elbow, I'm already gonna replace the tie end rods as they're starting to get a little worn. Flushing the transmission is also already planned for near future, as well changing oil in transfer case and the rest of the fluids. About the diffs, is there any intervals or recommended mileage for replacing the lubricant there? Or are they pretty much good to go "forever"?

When you say rear end seals, are you talking about the rear end of the engine? Anything that commonly causes issues there?

 

The rear differential doesn't ever need changing fluid unless it gets wet due to boat launching, etc. The vent comes off of the top of the left tube and winds up into the frame. Pretty hard to have that happen.
The seals I'm referring to are the wheel bearing seals. These have a tendency to go away after many miles.
If it's limited slip, a little more work when removing the spider gears but still an easy fix. Check your hubs for grease residue.

 

Ok, I'll check the seals around on the wheel bearings and such. It's an 4x4 with that AdvanceTrac option, and I'm not actually sure if that involves a Limited Slip diff, or if it's using that brake assisted traction thing where it's applying brakes to the spinning wheel rather than locking the diff. First time having a car like this, my older cars ('90 Caprice Brougham and back to a '63 Cadillac) always had limited slip diffs. If I remember correct, there's a tag or stamp on those that lets you identify the diff and if it's limited slip, does the diff on the Expy have something like that?

 

Yes, you have a tag on the differential as well as a door sticker with that same code on it.
For your year, I believe If you have an B6 or H9, you will have a limited slip rear end, 3.73 or 3.55 ratio.
If a letter doesn't precede the number, then it won't be LS.

 

If you have a floor jack lift the rear wheels off the ground. With it in Park and the e-brake off, turn one of the rear wheels by hand. If you cannot turn it you have LS, but if you turn it and the other wheel turns in the opposite direction then you have a non-LS differential.

 

I found this:

Two digit axle codes for Expedition:

First char - 1=open, H=LS
2nd char - 5=3.31, 6=3.73

My axle code is 16, so as I suspected it's an open diff, and luckily it's the 3.73. I believe that's a 9" axle. I read that the 4x4 with the AdvanceTrac RSC used open diffs and then featuring an "intelligent diff locking feature" they called brake assisted traction or something along those lines. It basically uses the ABS to brake the spinning wheel when it detects wheelspin. I have no idea how well that works, as now when I finally have a 4wd with that stuff, I live in a place where there's never under 20'C through the year, and basically never need it..

I know the trick of jacking up the wheels and turning it, but never had any need of doing it yet. Most my cars when I lived in Norway had LS diffs as it was a bare necessity if you wanted to drive anywhere during winter. Here in the tropics of the Philippines, you don't need anything like that unless you're planning to go crazy in the mud somewhere...

 

A well travelled man.
I have seen other's comment here on how well they like the Advanced Trac system for pulling boats out of the water, etc.
Sounds like you've got a nice set up, providing it doesn't break.

 

Well, I hope it's not gonna break anytime soon, it has around 58,000 km on it, which is about 36k miles. It shouldn't really have had any issues at all, but the previous owner hardly used the car in the last 5 years of ownership, I guess that was when the gas prices went up here. lol. Only one owner since new, but during that time it received little to no maintenance and at some point it had a minor collision damaging the left side of the front, where they decided to repaint the whole car. They did a decent job on the paint, but screwed up some of the wires here and there causing issues. I've fixed most of those now though.

But it really shows, little to no maintenance and stuff like that really screws up a car in the long run. Luckily all the major components are still in good order, like engine, transmission, transfer case and what not. Just have to catch up on the maintenance schedule. The last thing to fix is basically the intake runners and a vacuum leak which I hope is the intake gasket. Seeing that misfire reoccurring sometimes on cyl 5 does point to that, but may easily be a bad COP or boot, haven't looked at that yet though as I'll do that after the intake is fixed and confirmed good and sealed.

 

I wouldn't personally wouldn't "hope" the vacuum leak is the manifold. It could be the pcv elbow among other possibilities that are far simpler to fix.
Are there codes to help determine the vacuum leak, P0171/174?
I'd start there before wrenching on it.

 

Yeah, got a code for system too lean on bank 2 (forgot the code, maybe P0174?), same bank as cyl 5 which occasionally gives a misfire code. I need to take off the intake manifold to fix the intake runner control valve anyway, it's stuck closed on bank 1 so most likely broken clips, and Ford said the knock sensors were dead. Seeing the other electrical problems I have had and that BOTH sensors were dead according to them, I won't be surprised if that is bad wiring and not the sensors. I bought two sensors anyway so I wont have to wait for the shipping before re-installing the intake..

Since I've got those two issues warranting a intake manifold removal, I will have to replace that gasket anyway. The PCV is in the mail already somewhere, but the one on there is fine as far as I can tell. Since I have a lean on only one bank, and not both, it seems logical to me that the vacuum leak would be located in the intake after the air flow separates into the two banks, and an intake gasket would be the first place to look I think. I just hope it's not a crack in the intake manifold itself, since it's plastic, but I don't know how common that would be on these.

If the PCV is fine, the intake manifold is fine, and the gasket is fine, then I guess I need to start looking elsewhere for the problem... I do have the Ford Shop Manual coming, so I can follow the vacuum diagram and see if there's stuff connecting to the intake where the ports to bank 2 is. Hard to identify everything without anything to look at...

 

Lots of links here about those plastic manifolds cracking. Pretty common.
Good luck with the fix.