1998 5.4 4x4, low mpg, vibration, etc...

[kargh]

Hey Tbird,

Just got back from the weekend. Heres what I've done and the results so far:

Changed plugs and rubber boots but not springs. I noticed that there some sort of cylinder inside the springs on all the first on on the passengers side. I'm not sure what it is and the springs I got didn't have that (nor were they the same length, etc). I'm not really sure what that cylinder is or if its safe to toss and use different springs. So I left them alone. They looked in good shape anyways.

Changed oil.

Changed serpentine belt.

Changed PCV.

Seafoam'd gas and intake. Added through vacuum line, let sit for about 25 minutes then gave it a 25 mile drive. It smoked for about a mile or so and then nothing. Not sure if thats good or bad

Overall, gas mileage didn't seem to change. I think my little automotive computer is wacked though as its claiming my stepdad's truck is getting less than I am. I'm going to keep track of it manually for a bit. I really think I'm getting around 14mpg highway though. Not great but I do have the big tires on it and I've not had a chance to change out hte fuel filter yet.

It does seem to be running smoother and quieter though. Not a major difference but noticeable none-the-less.

So, thats where we stand. Didn't get to the diff change, tranny flush, transfer case or fuel filter yet. And my CD player cartridge won't eject.

[TBIRD430]

I'm not famiiar with the springs u speak of. Our '99 Exped didn't have them anyways. Try and blow through ur old fuel filter or tap it on the ground when u get around to changing it. Then blow through ur new fuel filter before installing it back....

=o)

[kargh]

Well, tried to do the fuel filter today. No go. The line out is frozen and I didn't have any desire to rip it apart in my garage.

[TBIRD430]

Soak the threads down good with a spray penetrate.

[kargh]

Originally Posted by TBIRD430

Soak the threads down good with a spray penetrate.

Threads? You mean the coupler where the clips are that you would typically be able to disconnect with the disconnect tool?

[TBIRD430]

Oh, our '99 had pipe threads on one end and a quick disconnect on the other side....

[TBIRD430]

Did u ever get the fuel filter changed "kargh"? How is this SUV running now? MPG?

[kargh]

Originally Posted by TBIRD430

Did u ever get the fuel filter changed "kargh"? How is this SUV running now? MPG?

Hey TBird,

Sorry, I haven't been around for several months here. Infact, I didn't do much with my truck since last time I posted until last weekend when I finally got around to changing the tranny filter and front/rear diff. So far it seems to be running quite a bit smoother. Can't tell its even shifting and that wierd vibration sensation when turning a corner seems to be gone but it always came and went so I'll know for sure in a few weeks.

I didn't get the fuel filter changed. I suspect I'll have to bring it in to the garage and they'll have to tear it out. I just don't want to spend that sort of money at this moment. Summer is expensive.

One thing I noticed, and perhaps you (or someone else) might have an answer to:

Theres a support that runs across the frame directly in front of the tranny pan. Infact, its kinda in the way and you need to reach around it to undo a few bolts when dropping it.

In the middle of this support theres two large bolts that run through it, about four inches apart. Are there supposed to be nuts on the ends of those bolts? It looks like there might have been at one time but they are missing now.

I noticed a long time ago that when I start moving or when I hit a large bump or turn a corner that theres a lot of creaking and groaning coming from somewhere under the truck, near the middle. I always thought it was just age but could it be this support not being tightened down and causing it to twist or something?

If there are supposed to be nuts on the ends, how tight are they supposed to be? And does anyone have any clue of the size so I can go buy a few? Any sort of washers or anything else?

Thanks, as always!
Jess

[dabigguy]

Hey Jess, with 118k miles it would be a very good idea to replace that fuel filter.....even if you have to take it to a dealer. Try doing it yourself again, maybe try a different type of fitting tool. The plastic ones sometimes don't do as good a job as the metal ones. You might be able to rotate the fuel tool slightly so the split contacts the "fingers" in the fuel line in a different place. There sometimes is a sweet spot that you have to hit.

If your truck is still running rough, it may be a bad coil. They sometimes become weak and it causes problems once the truck gets warm. Resistance should be between 4 and 10 kohms between the pins.

T-bird, these 5.4 engines have separate coils for each plugs. Your '99 probably had a 4.6 that has 2 coils that take care of 4 cylinders each. BTW, cool car !!

[kargh]

Well, I spent a long time on the fuel filter and theres just no room to really work on it. I've pulled and pushed and twisted and did just about everything possible to it that I could. I even took it to a buddies garage where he could get under it and he couldn't get it off either. I've read that sometimes those little fittings just lock up and all you can do is pull it off completely (fitting and all) and replace the whole works. I'll do it eventually, as soon as I have the money.

As far as running rough... its never ran rough. Its always ran remarkably well. Infact, right now it runs as if its brand new. Sure wish it got better than ~13mpg though

The clunking I get is definitely from the frame. I suspect its those two missing nuts. I need to figure out what ones I have to get and get a few to put on.

Originally Posted by dabigguy

Hey Jess, with 118k miles it would be a very good idea to replace that fuel filter.....even if you have to take it to a dealer. Try doing it yourself again, maybe try a different type of fitting tool. The plastic ones sometimes don't do as good a job as the metal ones. You might be able to rotate the fuel tool slightly so the split contacts the "fingers" in the fuel line in a different place. There sometimes is a sweet spot that you have to hit.

If your truck is still running rough, it may be a bad coil. They sometimes become weak and it causes problems once the truck gets warm. Resistance should be between 4 and 10 kohms between the pins.

T-bird, these 5.4 engines have separate coils for each plugs. Your '99 probably had a 4.6 that has 2 coils that take care of 4 cylinders each. BTW, cool car !!