That helped! It also cut down on the servo chatter quite a bit. It's not completely quiet now but it is much improved.

The car seems to snake/crab to the left while it's driving. Could be because I'm driving on carpet at the moment. Do you know of a good online resource for learning about setting up cars like mine? I'd like to know what the various bits do and how to make adjustments.

Thanks for your help so far! :-)