Vibrates a bit only in park or neutral

[tlee128]

Any ideas?

It's a 2003 Mountaineer AWD 4.6 with 140K miles. When in gear, no vibration at all. Things I've changed so far (was going to change anyway as part of high mileage maintenance): oem coils, platinum spark plugs, oem iac valve, oem mass air sensor, cleaned throttle body.

Could it be motor mounts?
Btw, anyone know how much to change all 3 motor mounts?
Thanks.

 

[Number4]

What are the RPMs at idle when you have the vibration?

 

[tlee128]

750 rpm at idle, very steady. If you give it a little gas in park, to 950 rpm, vibration goes away.

Also, besides previous listed items changed, I also put in a new air filter and pcv valve.

 

[D Hook]

Mine does the same. Occasionally.