Notice that Paul writes, "When we were in the flesh." Were. Now look at Romans 8:5-9:
For when we were in the flesh, the motions of sins, which were by the law, did work in our members to bring forth fruit unto death.
5 For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit. 6 For to be carnally minded is death; but to be spiritually minded is life and peace. 7 Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be. 8 So then they that are in the flesh cannot please God. 9 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
So much in these verses plainly says a carnal Christian does not exist. He isn't after the flesh. He doesn't mind the things of the flesh. He isn't carnally minded or in the flesh any longer. Sin does not have dominion over the believer (Rom. 6:12). A Christian no longer lives sin as a lifestyle (1 John 3:6-10). A child of God is a new creature, old things are passed away and all things are become new (2 Corinthians 5:17). The person he once was is crucified with Christ (Gal. 2:20).
The moment someone receives Christ, he has every spiritual blessing in heavenly places in Christ (Eph. 1:3) and all things that pertain to life and godliness (2 Peter 1:3). The Holy Spirit is a Person, not a power of influence. The moment someone believes in Jesus he receives the Person of the Holy Spirit, all of Him. He won't receive any more of Him. He doesn't need anything more than He has in order to live the Christian life.
Justification isn't a two step process. Someone doesn't receive Christ as Savior and sometime later as Lord. He doesn't allow the Lord in but not on the throne of his life. No one can remain in rebellion against the Lord Jesus Christ and be saved. Confessing Him as Lord is more than Words. It is more than just intellectual, but also volitional. It is relinquishing allegiance to sinful self.
Every single believer has the power to obey everything Scripture tells him. We don't have to wait for salvation to "click," to "sink in," or to "really take hold" in order for the child of God to submit to any and every truth in the Bible. In order to gain eternal life, we have to give up our temporal life. For God to cleanse our soul, our self, we must give it up to God by faith. If we hang on to it, God won't restore it back into the righteous state He intended it.
Those who won't give up their life aren't carnal Christians. They're just carnal. They walk after the flesh and not after the Spirit (Rom. 8:1). They won't have the power to live the Christian life either. And that won't come when they have revival or receive a second blessing or get the baptism of the Spirit. However, when they do receive Jesus for Who He is, He will save them and immediately give them victory for their Christian life. It will be a struggle (Romans 7:21), but they will conform to the image of His Son even as He predestined them (Romans 8:29).