Gravel feel when accelerating

[Shantheman73]

Hey all…weird symptom I’m experiencing.
When I’m accelerating hard, I get this gravel rough feeling coming thru the gas pedal…almost like it’s coming from front diff or maybe the axle trying to engage 4x4 or something. Under normal acceleration it feels normal and smooth as always.

It shifts fine in either circumstance, but maybe its torque converter related? Front diff?
It’s a 2007 Limited 4x4

 

[Shantheman73]

Bump. Curious if anyone has any thoughts. I’m wondering if it could be engine related too…since I’m feeling it thru gas pedal?

 

[Trainmaster]

When was the last time the infamous spark plugs were all changed? My initial thought is that it is a miss. Nobody likes changing those plugs, so if you didn't change them yourself it's quite possible that they have not all been changed any time recently.

 

[Shantheman73]

When was the last time the infamous spark plugs were all changed? My initial thought is that it is a miss. Nobody likes changing those plugs, so if you didn't change them yourself it's quite possible that they have not all been changed any time recently.

Good thought. I had Ford change them about year and half ago…20k miles ago.
It also had a bad coil pack at the time…and I recall what that felt like. This is definitely different. ‍

 

[Shantheman73]

The more I think about it…it’s gotta be engine related. Would coil packs cause this type of behavior when they go bad? The last one that went bad…it just caused hesitating at certain RPM’s. What other symptoms might point to bad coil packs?

 

[sjwelds]

I think it could be related to the 4wd system. It is vacuum operated, and there isn't much vacuum under hard acceleration.

I had similar issues with my 2012 and a new vacuum check valve fixed it. I will say that I never felt it in the pedal tho, it was more of a noise that I'd hear that I knew wasn't quite right... Ymmv

 

[Trainmaster]

The more I think about it…it’s gotta be engine related.

A miss of any magnitude would be picked up on a good scan tool. Certainly could be a bad plug or bad coil, as I said earlier. A good scanner would show the number of misses in each cylinder.

 

[Nickp33]

This happened on mine. Mine was a wheel barring on front left wheel. Would have sworn it was something different at the time. Good luck.

 

[Goofy173]

Yes. Wheel bearing. They'll be felt in the pedal and usually the steering. May change on acceleration, braking, and /or turning.

 

[Dustin Gebhardt]

This is probably the IWE's engaging partially under low-vacuum conditions. I had the exact same issue in my '07 and I discovered that my vacuum line running across the front crossmember had a hole worn in it. I fixed the line and everything got better.