sounds like AFM. When you pass over bumps in the road it can wiggle the wires to the AFM just enough that the solder joins lose contact. With my car i can just touch one of the wires and the car stalls.
Also, when the car 'jitters' the air isnt being metred properly thus playing havoc with air/fuel ratios and no power/chugging.
you can fix it with a soldering iron and solder. take apart the AFM and re-solder the pins that connect the AFM to the wires. if youre confused, see the tutorial section