You say it's not sputtering before it dies, this eliminates it being rich.

If the revs fall off quick as you go wide open, but you can catch it if you bring the throttle back down real fast, then it's real lean on the top end.

If the mix is fine, it just flat dies (idle to full) in the air or on the ground and has to be run as lean as possible to stay lit, try a fresh jug of fuel and a new A3 at the SAME time.

The bad fuel will ruin a new plug until it's run on fresh fuel for at least 3 tanks.

Kirk