Vauxhall Zafira stalling

Could be coil pack , quite common .Numerous other possible causes ,best to get a diagnostic scan rather than guessing and replacing parts .

The most likely cause is the idle air valve which is part of the throttle body.

You may be lucky and it's only a build up of sludge stopping the valve from operating, so your first job is to take the intake pipe off of the throttle body and using some carb cleaner with a long squirty pipe, give the valve a good squirt. Put the pipe intake pipe back on, fire it up, and check. If it still does it, try again.

If the carb-cleaner doesn't do the trick, then the valve is faulty and requires replacement. depending on the model, it could be a separate valve, or a complete throttle body.

There is also a chance that the exhaust recirculation valve could be causing it too....

If you car has air-con, a quick "get me out of trouble" fix is to turn the air-con on. That lifts the revs at idle, and it doesn't stall quite so often!

The reason that works is that it opens the idle valve a little further, and in that state it doesn't stick shut causing the engine to stall.

You have to remember that these engines don't have adjustable idle stops on the throttle flaps, so tick-over is done electronically, using the air valve to do the work.