Buying 2007 Yukon 5.3

[NGAneer]

The rough idle/vibration seems to be worse at idle with it in gear. While in park it's hardly noticeable. Would that be consistent with a motor mount?

Could be, but it also could just be how it idles. Mine, especially when cold has a little shake at idle. Nevertheless, having it in gear would make the wobble more substantial if it were a motor mount.

Put it in drive, lock down the e-brake and hove somebody rev it with the hood open. Stand beside the truck and look and see if the motor tries to rise up on one side. Then do the same in reverse to check the other side.

 

[bills02yukon]

I tried that and the motor will move slightly. Maybe a 1/4" or so

 

[NGAneer]

Sounds pretty small for a motor mount to be broken.

 

[bills02yukon]

I guess it's just the nature of the beast. I was going to ask my local GM service department if changing out the throttle position sensor would change anything. I know there was a tsb for 2008+ that had a rough idle

 

[NGAneer]

I guess it's just the nature of the beast. I was going to ask my local GM service department if changing out the throttle position sensor would change anything. I know there was a tsb for 2008+ that had a rough idle

If you've got a scan tool, or even just the Torque app. You might be able to glean some info from what the TPS or fuel trims are doing. Otherwise I'm out of ideas.