jimmy jacking around

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!