Pulsing/bumpy ride

Joined
Jan 27, 2004
Messages
4,131
Location
Richmond, VA
This problem is on my 2007 Mustang GT, Auto Trans, 102k miles.

This problem is almost always present, but it seems to get much worse without any warning, sometimes it is hardly noticable. Cold weather seems to make it worse.

There is a bumpy/shuddering feel when I go above 35 mph, above 60 it is twice as bad as 35mph. Above 70 is no worse than 60. It feels like someone is hitting the bottom of the car with a rubber mallet. On Super smooth roads it is almost non existant.

No CEL, engine seems to be running perfectly. BUT I recently put the car on ramps and put my hand on the oil pan and it seemed to be vibrating more than what I thought it should. Maybe motor/trans mounts?

Acceleration, constant speed, and decel are about the same, braking does not seem to make it any better or worse.

The tires were my first suspicion but I replaced them in the spring and while it did make the problem much less noticeable, it is still there. Have balanced them at Discount Tire twice.

When going down the road at 75mph I put the car in Neutral, problem was still there.

Replace rear lower control arms since one of them had a bushing that looked really bad. Did not help at all.

Replaced the original rear shocks a couple of weeks ago. Did not help.

Last weekend I looked at the Differential mount and bushing - it looks bad - but I'm not a bushing expert. Maybe this is the problem?

This morning on the way to work as I was getting on the interstate (heavy accelleration) it was as bad as it has ever been. Felt like one of the wheels was going to hop off the car. Came to a stop, made sure one of my tires was not flat, got back in and drove 25 miles to work and the light bumping was still there, but not bad at all.

I am at a loss, maybe it is the differential mount bushing, maybe it is a stuck caliper, maybe it is a transmission shudder. Open to ideas and suggestions.
 
Forgot the mention, this morning when it was really bad, my steering wheel was vibrating back and forth Really really bad.
 
If it were transmission shudder, it would go away in Neutral.

Vibrating the steering wheel would make me look at the front end. Tie rods, rack, front control arms, front wheel bearings...
 
I wonder if it's your upper strut mounts? I knew a guy with a Mustang about that old, and his strut mounts needed to be replaced. Ford published a TSB on the subject.

Anytime I've had a car over 12 years old that is driven regularly, I've found it beneficial to replace ALL the wear items in the suspension (bushings, ball joints, structs/shocks, and even springs). Also any motor mounts, trans mounts, or subframe bushings with rubber in them. It makes a huge difference to refresh those items, and it's not terribly expensive if you DIY.
 
I wonder if it's your upper strut mounts? I knew a guy with a Mustang about that old, and his strut mounts needed to be replaced. Ford published a TSB on the subject.

Anytime I've had a car over 12 years old that is driven regularly, I've found it beneficial to replace ALL the wear items in the suspension (bushings, ball joints, structs/shocks, and even springs). Also any motor mounts, trans mounts, or subframe bushings with rubber in them. It makes a huge difference to refresh those items, and it's not terribly expensive if you DIY.
Thanks, That is one item I have also considered - and last week I read the TSB. Motorcraft quick struts are only $300 from Rockauto.

So far, I have done all the work - but my shoulder has been killing me lately so I want to make sure I am only doing what needs to be done for now.
 
I'd also check the rear upper control arms and diff bushings. They cause a lot of squeaks and creaks on the previous generation Mustangs
 
I'd also check the rear upper control arms and diff bushings. They cause a lot of squeaks and creaks on the previous generation Mustangs
I did a visual inspection of them this past weekend. They do not look good at all - BUT I am not a bushing expert.

Could they be so worn that it caused my rear end to get slightly out of alignment (under heavy acceleration) and caused my steering wheel to shake?
 
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