On start up engine dies as if stalled. Engine stays on if you turn ignition then rev it for a few seconds only dose this about once or twice a month regardless of weather (ie damp etc) and how much fuel is in it. Subaru have had it 4 times and cant find a fault.I have changed spark plugs and leads any ideas?

 

Does it ever do it when stopping at junctions / pulling up etc? Is the idle quite steady?

MB

 

Idle seems fine. Only happens on start up once

 

Sorry ment to say only happens on start. It has also happened when engine is warm ie went into pay for petrol came back out wouldnt start, had to turn ignition over for a few secs then you have to rev for a few seconds to keep it on.