It was resting on top of part of the throttle. some kind of copper tube that appears to run down and connect to some kind of switch on the transmission. It lines up right like it would have been connected to the throttle some how, but it's not a bolt, so not sure how it would get it back on. Tried digging in the shop manual, but no decent pictures for my car... on that note, is there a good book I could buy that's more specific to a 69 fastback with more picture / diagrams? Shop manual having 5 different car types doesn't help, and most of my other books aren't for a specific year mustang. Sometimes I can find good diagrams online, but looking for something I can bring to the shop without killing my printer cartridges.

 

That is your kickdown linkage for the transmission. It's attached to a lever on the trans and is what makes your car go into "passing gear" when you mash on the gas.

 

Thanks, will dig around in the shop manual for it. that and the timing advance vacuum hose being disconnected explains why it's get up and go got up and went on the highway.