Messing around, especially when it comes to a job or important activity. Could also be a reference to beating a dead horse when it comes to getting a machine or important piece of equipment to work.
Steve said that Dave was jimmy jacking around so he got yelled at. Because Dave's a lazy fat nerd and nobody likes him.
Look I'm not going to jimmy jack around with that head gasket, just get an expensive mechanic to do it!
slip of the tongue perhaps,
Those idiots who drive around in a ridiculously raised pick up truck, making a top heavy vehicle even more top heavy and unstable
A:*gah*
B: "Whats the matter"
A: This dam prickup is blinding me.
B: Stupid thing's, as if there lights weren't blinding enough as it is.