A 'dead' faith cannot save one from physical death as stated in Jn.15:2, God will remove those not producing fruit. I'm not sure that I read the verse quite that way. : John 15:2 Every branch in me that beareth not fruit he taketh away: and every branch that beareth fruit, he purgeth it, that it may bring forth more fruit. KJV Now, the NIV, which I normally quote, says "cuts off" rather than "taketh away". That makes this a little more difficult for me. Nevertheless, I have taken either phrase to mean general discipline by God, or possibly death, as you see it. The problem I have with the death option is how to reconcile it with (POTS) verses like Phil. 1:6. He carries the good work on to completion. The death option appears to imply that man can thwart that good work begun. I don't think I can buy that because it would seem to destroy POTS. However, there is logic in your reading since "pruning" is specifically and separately mentioned. Frankly, I'm not sure what the best explanation of this verse is. :) Moreover, one can have a 'dead faith' and still be saved as shown by 2Tim.2:13, 'if we believe not, yet he abideth faithful; he cannot deny himself', indicating a believer who has lost his faith, yet remains saved. "Dead faith" is probably too strong for me. :) To me a dead faith is a false faith, is no faith. I don't think we can completely lose a once held true faith. We can wander or suffer, but I don't think the scriptures teach that we can totally abandon the gift of God. We are, after all, a new creation. We are permanently changed, for all time. God will complete the good work He began by taking a believer to heaven once he has accepted the free gift of salvation.
There are clearly cases where believers have been dealt with with physical death, such as in Acts 5 and the believer turned over to Satan in 1Cor. 5 (but who avoided death by repenting of his sin).
Paul states that taking the Lord's supper lightly can result in death (1Cor.11:30-many sleep).
John states that there is a 'sin unto death' (1Jn.5:16).
One can lose his 'active' faith by quenching the Holy Spirit (1Thess.5:19), but not His salvation, since he is sealed by the Holy Spirit (Eph.4:30).
What he loses is the rewards at the Judgement seat of Christ (1Cor.3:12-15, 2Jn.8)
The unbeliever does not have a 'dead faith' he never had any faith