The only code showing up is a P0303, What do you mean when you say HLA engine ?
This car is a 1998 Legacy GT it was built with a 2.5, A previous owner did a swap to a EJ22.
I only know that because I can read it on the block.
I think the engine is a 1996 because the spark plugs do not go through the valve covers making it a non interference engine which were built 1990-1996
Also I think it has single port exhaust making it a 1995 or 1996.
Do you think the miss could come from a improperly seated intake or exhaust valve?
As for the injectors I do not own a noid light but i did check #3 with a test light and a meter for voltage.
With the key on I had constant voltage when the engine was running I was seeing a pulse on the test light.