sardis51

I was given this truck by my wonderfull brother.He is in the millitary and had to leave this truck in the care of our mother for a couple of year prior to giving it to me. I have noticed that the motor makes a noise as I am moving and increases as speed does. It almost sounds like when a motor is stalling that rattle. Just not as loud. does anyone have any advise on what it could be and if it is going to cost a arm and a leg? thanks

kelownaF150

Your description of the sound is vague...A rattle upon acceleration is usually the valves...the timing may be too far advanced and/or you have low octane gas which may also cause valve rattle. I'm not sure if it has a knock sensor but that can cause it.

Another cause for rattling noise can be from the exhaust.

Good luck

97green4x4

Good day,

I agree with KelownaF150 that it is a little vague... Where is the noise coming from? Motor, trans, drive shaft, rear, wheels, suspension, body?? Does it go away if you put the truck in 'N' when you are moving? The 4.6Ls and 5.4s have issues with popping the manifold bolts causing a leak... There is a knock sensor in the valley under the intake, however it could still be fuel... Do you get a check engine light with it running?

Cheers!!

sardis51

The nock is in the motor. and I get no check engine lights at all. I also put a high octane and injector cleaner in it and have tried to do that for about 5 weeks and no change in the nock. I drive it and it will not nock unless I am accelerating fast, pulling a load, or going up a really steap hill. I changed the spark plugs and 3 of them had oil on top of spark pulg. I couldn't see any leaks though. It seems to not have as much power as it use to have but it also has 130,000 mile on it. If there is anything else you all can think of then please let me know. I will check. thanks

Cain

could be the lifters chattering.. with oil on the plugs i would guess valve seals.

97green4x4

Good day,

First, I would change the oil, but use 10/40 or heavier... I'm thinking that you need to replace the rod bearings before it gets worse! This is what I would do. Figure out what bearing needs to be swapped by either pulling the fuel injector connector, or the plug entirely, one at a time (replacing each as you go)... Rev the motor each time until the knock isn't there when you rev the motor. If the knock goes away, then that is the bearing you need to replace... IF the knock doesn't go away, it may be the timing chain or the bearing is beyond it's limits to keep it from knocking under normal rotation... I just bought a truck that had that very problem... IF it doesn't knock under idle, you may be okay just finding the bearing and replacing it, or replace them all... The oil on the top of the plug is the valve cover... easy fix... Oh, in addition, the truck may be running like it has no power because the computer is compensating for the knock the "knock sensor" is detecting...

I have two 4x4's... my 97 (bad motor) and a 2000... I had to replace the #8 rod bearings in my 2000... I replaced it with the motor in the truck... She is running strong to this day...

Let us know what you find out...

Cheers!!

kelownaF150

Sounds like a connecting rod...

As for the 97 4.6 being a bad motor, I couldn't disagree more! -I have 290,000 km's on mine; that's approximately 164,000 miles!.

After pouring Seafoam gas treatment through it and 6 oz/tank of a home made concoction - 2 parts acetone 1 part xylene 1 part synthetic two stroke oil - it runs smooth as silk. It's now responsive to the slightest touch on the gas peddle.

I have done nothing to the engine aside from plugs and wires.
I have the oil and fluids changed regularly. > Hate where the oil filter is.
The engine is hard to service. > Placement
Don't like the few threads that hold the plugs. > Poor design
It's hard on gas - 8-14 MPG
Ive changed the breaks 2X (took me 1.5 hrs without power tools)
I have changed 5 struts (1 - 2x)
I changed the battery and a fuse.
Oh yeah I thought I had to replace the starter but turns out the connection wire broke off.
I pulled a travel trailer or a boat.

The body and paint is still awesome. (Dry environment)

It has been absolutely dependable both on and off road.

97green4x4

KelownaF150,
I'm not sure if you are referring to my post about the 97(bad motor) in your above response... If you are, I didn't mean the motor, as a whole, is bad... Just the one that was in my 97... I love the 4.6L and 5.4L motors... they have their flaws... many of which you have stated... Plugs breaking in the 5.4L's... But over all, they are great motors!! The motor that was in my 97 didn't have any bearing left on the #8 rod... the lack of the bearing ground the crank down so far that the piston made contact with the swirl fin cast into the cylinder head... Rather interesting, to say the least!!

Well, have a great Thanksgiving everyone!!

Cheers!!