2004 F150 FX4 5.4

I'll try to make this short.
Vibration in steering wheel in overdrive under load.
I let off throttle, it stops instantly.
Replaced coils twice. Just got it back from local dealer.
They did a smoke test for vacuum leak. Nothing.
Checked for codes. Nothing. When this happens there is no
shudder, missing ,etc. just steering wheel vibration.
The more load the worse. Any other time it is fine.
All steering components tight. Bad steering pump?
After 2 different Ford dealers, and said mechanic
are stumped. Oh yeah, this happened literally
after major engine work by Ford dealer...Also,
I just bought 8 new Motorcraft coils just in case.
But they are not installed..
Any ideas?

Vance

 

How many miles on the plugs?

 

First thing I'd check is to make sure the weights on driveshaft are still there

 

What was the extent of the "major engine work" by the dealer? Was it cab off to remove the engine?

Also check the engine oil level if there is to much oil in the pan (overfill) you will get vibration in the steering wheel under certain conditions.

 

Replaced when dealer did engine work. 6 Months ago..

 

Engine was no pulled.
Replaced cam, some lifters, chain, etc..

Oil level is fine..I always change it myself.

 

I'll check it out..

 

Weights all intact..

Vance

 

One thing I forgot to mention is, the idle is alittle rough.
Nothing major, but it is not consistent. Some times worse..
Also the steering vibration happens no matter outside temp.

Thanks Vance

 

Check the u-joints. Under load they could cause vibration which would go away when not under load.

 

When I was at one of the Ford dealers, they found rear U joint lose.
They replaced it...Still same problem...I went under truck and yanked on the drive shaft. Front to back, side to side, and no play..
Thanks

 

Also the mechanic, ( not Ford dealer) Spent an hour going back and
forth with me as to possible problems. He suggested several things, but was not sure of those either. He told me he was not "going to throw parts at it" until he can figure it out.
BTW, He specializes in trucks. I've had other work done by him and
he fixed all problems. 100%...That's why I always go back to him.
I would NEVER Go to Ford dealer because I found out the hard way, they are idiots!

 

BTW,
He has been working on trucks for 25 years, and never came across this problem..He has all local businesses, from big trucks, to trucks like mine go
to him exclusively. He is always busy...So he is not a fly by night business.

 

Is your truck 2- or 4-wheel drive? Could be an issue with CV joints in the front axles if 4-wheel drive...

 

If it happened just after the engine work, i would suspicion the engine work.