Vibration and shaking - need input on possible causes

[sasquatch]

I have a noticeable shake/vibration which is worse at low speeds. First thing in the morning when I'm leaving the house it feels like the wheels are severally unbalanced...the car wants to bounce up and down. I had the tires replaced a few days ago and balanced twice but it is still there. The tire place said the wheels did not appear to be bent. So, I'm suspecting something in either the suspension or maybe the driveline like the drive shaft and carrier bearing. The problem seems to be speed related. I'm at a loss right now. Any suggestions besides the obvious "bent wheel"?

[gerry_miranda]

Did the tire place do a road force balance?
Sounds like a flat spot.

[sasquatch]

I honestly have no idea. It was done at Discount Tire so I assume they have the good balancing equipment. These are brand new Falken tires so I'm kind of doubting it is the tires.

However, it does seem to be worse in the cold morning. And it was there before I got the new tires.

Would worn thrust arms/bushings cause this type of problem?

[3Series]

Fuel Injectors dirty?

If at idle, bad motor mounts?

Dirty Idle Control Valve?

[Nik]

Yes, I Would say check motor mounts. Fuel injectors may also be. Today I had my car sitting with low fuel (32range) and when I went to refuel, after refueling car would crank and keep craking and did not start. Twise, then it started and ran normal. Injectors?

[ValveTronic]

Check your tire pressure. Too low can cause flat spots.

[sasquatch]

I'm religious about check tire pressure. Exactly 32psi in each using a accurate gauge.

The vibration is worse around 20mph and settles down the faster I go. It's still there but not nearly as bad at, say, 60mph. It's more noticeable on smooth, flat road.

I wonder if the wheels are not seated correctly on the hub. It's a tight fit between the wheel center hole and the hubcentric part of the hub. I've cleaned both surfaces to make sure there is not build up and corrossion but still pretty damn tight. Might try grinding off a little material using a die grinder with cleaning wheel.