overland

Hello folks,
My 2008 F150 (4.6L) experiences high frequency vibrations starting at 55mph and peaking around 60mph and going away by 80mph. It is worse when I take my food off the gas pedal.I have had the wheels balanced. There is no vibration in the steering wheel. Any ideas? Thanks.

BadFish523

Any misses> A lot of times people confuse a miss with a vibration. Also could be your drive shaft, or the wheel balancing. Did you have the wheels balanced with I thinks its called a Road Force balance? Sometimes tires are picky and from what I've read this is the best balance you can do.

overland

Thanks StephenG,
I don't think it is missing, as it runs smooth at lower speeds and at idle. I had the wheels balanced and that didn't change anything. I've heard if Road Force balancing, but I have no idea what it is.

BadFish523

LOL me either just heard it is much better than a basic balancing job. Do you have any means of reading misfires. A lot of people only notice them at higher speeds.

overland

Not that I am aware of, although I am thinking of replacing my sparkplugs (I bought the vehicle only a few months ago).

jshillin

iTrader: (1)

Did you try to swap the back wheels to front and front wheels to back? IF it's a bent rim on the back, you wouldn't feel it in the steering wheel.

overland

good thought jshillin,
I believe the wheels were rotated when they were balanced.

brokenarrow

It sounds like it's not wheel related if you had a rotation done and the vibration hasn't changed. As SG said, the driveshaft can throw a weight and cause these vibrations, which would stay constant after a tire rotation/balance.

Does the vibration feel like it's coming from the front or the rear? Does your steering wheel shake?

Try shifting into neutral when it happens. Also try shifting out of overdrive. This can start to rule out the transmission as an issue. Basically, does it happen at different RPM's or when the tranny is engaged.

Right now, there are too many variables, lets start checking some of these things off to pinpoint a system.

I had a similar issue and ended up solving it with a lot of help from the guys on here. We'll get it figured out!

overland

Thanks brokenarrow,
I have noticed that the vibration intensifies when I take my foot off the gas.
There is no steering wheel shake.
Shifting to neutral makes no difference to the vibration.

brokenarrow

It sounds like based on your observations that you can rule out the engine/transmission and isolate it more to a rotating part like the driveshaft.

Are your front end components in good working order (ball joints, wheel bearings, tie rod ends- inner and outer, stabilizer end links, etc)? Does the vibration change in 4WD (if you have 4WD)? The vibration in my truck was the IWE's being constantly engaged. May be worth while checking that out as well.