What are the biblical arguments that if you sin you lose your salvation as soon as you sin?

Methodological considerations

I think I understand what you're trying to do: you are creating your own theology based on your own interpretation of the Bible, and you're wondering whether there is an existing branch that matches your interpretation. You also want to bolster your theology with further Biblical arguments. You are thinking that Pentecostal theology is the closest to your theology. But I agree with @Matthew's comment that this view is not mainstream Protestant, and as I argue below, it's actually close to Catholicism!

From your writeup, I can see how your notions of grace, salvation & sanctification, body vs. spirit, and how the Holy Spirit works within us are rather different than established Protestant theologies such as Reformed, Lutheran, Methodist, and even Pentecostal! Hence I agree with @DJClayworth's comment.

While everyone has a "right" to create their own theologies based on extreme form of private interpretation of the Bible, most Christians don't read the Bible in a vacuum. They would

• try to exegete carefully how the Biblical authors themselves define theological terms like grace, sin, justification, holiness
• dialogue with communally respected theologians like Martin Luther, John Calvin, and John Wesley to "tweak" the theology of how God works out our salvation through the ministry of the Holy Spirit
• create a theological model of the human person that fits all the empirical facts as well as how grace & sin operates within that model
• read at least one systematic theology book that bring a certain cohesion to Bible interpretation as well as showing connection with common topics in theology, showing you a link between Trinity, the Fall, Salvation, and Eschatology, for example.

Comments on your view from the perspective of common Christian theologies

1. Most Protestants (especially Wesleyan and Pentecostals) as well as Catholics believe that sanctification (growth in holiness) is gradual and that there is some level of cooperation of our will with the Holy Spirit who infuses grace to our being to make us conform closer to the image of Christ. So the "enablement" you speak of is not a switch, despite Pentecostal practice of Spirit baptism (equivalent to Catholic sacrament of confirmation). Progress and backsliding is very much a reality, and should not be construed as a loss of salvation, because unless the sin is "mortal" (understood in Catholicism) or unless we "grieve the spirit" (understood in Protestantism), the life of the Spirit remains within us despite the influence of our remaining sinful nature.

2. Sola Fide refers to justification: reconciliation with God, and an imputation of blamelessness / righteousness before God. Works is our response, and is not part of justification. Instead, sanctification (understood by Wesleyan & Pentecostal) should be heavily linked with union with Christ, who through his Holy Spirit imparts his grace that in turn empowers us ("empower", not "enable", to highlight the synergism) to choose and do good.

3. In Catholicism, when we sin "venially" we don't lose salvation. But "mortal" sin is the working of our soul that has so reject God that we are most likely lost before we sin ! For example, a person planning a premeditated murder has probably already lost his salvation before he carries out his act.

Answering your question

You asked:

What are the biblical arguments that if you sin you lose your salvation as soon as you sin?

If the sin is "mortal", the Catholic Biblical argument can be read in a Catholic Answer article by Catholic apologist Tim Staples Mortal and Venial Sin? citing Catholic interpretation of:

• James 2:10-11: the context of James 2 doesn't allow one to say that all sins are equal, but simply that one cannot pick and choose which laws to obey

• Matt 5:19: Jesus makes a distinction between "one of the least" of these commandments where the offender still remain "in the kingdom of heaven". This becomes the basis of venial sin, which contrasts with a mortal sin that Jesus described in Matt 5:22 with the consequence in vv. 28-29.

• Matt 12:32: This is the famously controversial verse about speaking against the Holy Spirit that cannot be forgiven, again contrasting less vs. more serious sins. In contrast 1 John 5:16-18 teaches that venial sins are not "deadly":

  If anyone sees his brother committing a sin that is not a deadly sin, he will ask, and God will give him life for those whose sin is not deadly. There is sin which is deadly; I do not say one is to pray for that. All wrongdoing is sin, but there is sin which is not deadly. We know that anyone born of God does not sin, but He who is born of God keeps him, and the evil one does not touch him.

I know this sounds like a doctrine of salvation only by works, but it is the grace of the Holy Spirit that enables us for these works. I would like to know if there are more biblical arguments for this and if this branch has a name

While Catholicism is not salvation ONLY by works, Catholics are super serious that the Holy Spirit works in manifold ways (including through sacraments) to empower us to become more holy. This point, and the above point about losing salvation, is the reason why I suggest that the name of the branch you're looking for is Catholicism, as @Matthew also suggested.

But if Catholicism is not for you, I recommend you choose a systematic theology book written from a Protestant theology you trust. For Pentecostalism, one example is Stanley Horton's 1994 book Systematic Theology: A Pentecostal Perspective.