jagger_cn

I have a big problem of my 1996 c280,sometime when I hit the brake,it's complete shut down,but sometime not.and sometime it was easy to start again,but sometime was hard.there was no error code on meter.i have changed fuel filter,but no effect.someone tell me to change the CRANKSHAFT POSITION SENSOR, someone tell me to change the Spark plug.
i have no idea about it!
who can help me?
any ideas appreciated

jagger_cn

and when it shut down,sometime the temperature of water tank was low ,sometime was warm.