So if I user my primary weapon to attack and then vader and kill myself, can I still gunner and vader again even if I'm already dead?

I believe you have to have at least one hull point left to Vader.

It's covered but in really woolly and not correct language (they use the term 'one hull point left' whereas in x-wing you don't lose hull as you accumulate damage, you just die when you have a number of cards equal to your hull), under the FAQ for Darth Vader crew IIRC. Basically you can kill yourself with Vader then use Gunner, but if you do you can't Vader a second time.

Although it is still possible to attack, use Vader, then Gunner and then succeed in killing yourself with a second Vader attempt.

I believe you have to have at least one hull point left to Vader.

Which would mean you could use Vader on both attacks as ships almost never lose hull points. The FAQ really missed the ball on that ruling.

A ship with Gunner and Vader with damage cards one short of its hull points could attack, triggering Vader, and miss, triggering Gunner. Despite Vader's damage going to kill it the Gunner attack is allowed which in turn SHOULD trigger Vader again but that is NOT what the FAQ wants you to believe.

Whether or not the faq is worded correctly, I think that rules as intended is pretty clear here, you need to have less damage cards than hull to use Vader.

Thanks everyone