I've used a Karcher in the past, and it has been fine. It never cuts out. I've since given it out on long term lend, so I have to guess the model - K 2.300.
A word of warning on washing your car - pressure washers are fine for getting it wet, knocking off mud, and for rinsing the soap off afterwards, but so is a regular hosepipe to be honest. The pressure washer is no substitute for elbow wax - if you use the highest pressure nozzle, it'll likely strip some paint too.