On random occasions my absolutely standard 1998 Scooby turbo will stall when I pull up for a traffic light. It will restart but on one or 2 cylinders only, with a lot of misfiring. After about 30 seconds of dabbing the accelerator it suddenly picks up on all four and runs perfectly. Normally starts and runs perfectly well with no obvious problems with fuel consumption, loss of fluids or any other possible clues to the fault.

Any thoughts as to which of the many sensors might be in trouble - or should I be looking for water contaminated fuel pehaps.

Could be Cam or crank sensor related. Is it more prone to stalling when hot?

Its happened 3 times in the last 2 months, but never before in 17 years. Both the car and the weather were hot each time, but that's nothing new. There was one incident during cold weather in spring 2015 when it refused to start from cold, it was just cranking with no compression evident, which an AA man   overcame by churning the motor on full throttle and diagnosed a sticking air flow valve or sensor. My service agent could find nothing wrong. It has not happened again.