Bad and dangerous! First, many things including the steering sytem either lock or shut down. Just about everything that uses the elctrical system is shut down...and many of these things run things, like fuel pumps, etc., that the engine needs.
What causes a car to jerk while driving can be based on many factors. A car can sputter due to engine compression issues, bad transmission, engine misfire, bad spark plugs or even low fuel.
have brakes check
One reason that a 2000 GMC Jimmy engine stalls while driving could be your filter needing to be changed. The problem could also be a bad sensor.
probably a bad camshaft sensor.
Alot of things.. bad gas.. No gas.. Engine is dead.. etc.
You risk turning a minor problem into a major one. Get it looked at ASAP.
A bad timing belt could make the engine shut down but it would only happen once, not sometimes.
one reason could be a bad ECM (Engine Control module). Replacing it is easy. You can do it yourself.
Usually a sighn of bad alternator.
Year, make, model and engine would help but, a bad timing belt or a bad fuel pump could do that.
A flashing service light (called a MIL or malfunction indicator lamp) indicates misfiring has been detected. DO NOT DRIVE THE CAR $$$$$. Get the misfiring repaired, could be bad coil or coil packs, bad wires, bad plugs. Driving with misfire can destroy the catalytic converter.
Bad gas, fouled plug(s), engine out of time, vacuum line leak or clogged.