[washington dc ML]

I'm wondering is it my tires that are out of balance or a motor mount. Could it be anything else, especially if the engine is vibrating at idle?

 

[sosh]

Could be either or both.

 

[xwing1124]

You might want to look at the harmonic balancer - others have had them fail - thats my explain the vibe at idle - but the vibe at speed - that sounds like a wheel out of balance .

Barry

 

[dakat]

You don't mention your mileage, but a 99 must have several thousand. I'm sure you're in need of spark plugs and/or wires! Fix the idle problem first and see what that does to your 60+ problem. A V-8 with 1 or 2 cylinders down will shake at higher speeds too!
Just my 2 cents......good luck!! [8D]

 

[washington dc ML]

Thanks, and yes as of this moment I'm at 67K miles.