Does my sentence sound right?

The strange ??? behavior is completely throwing me. I don't know how to troubleshoot it.

I suppose you meant "electric"? I'm not sure about this word. What exactly are you describing?

I was supposed to say " the strange electric behavior is completely throwing me off" I wanted to say "throwing off" as " confusing"

"throwing me" in your original sentence is correct.

However, it is the word "electric" that I am unsure about. I suspect that "electrical" is better, but I would need to know what kind of situation you are talking about.

The electirical signal randomly fluctuated, showing the part has a problem

In that case I would say "strange electrical behavior" (note spelling).

Lack of quality of service

This post, by the way, should not be here. On the Forums it is much better to start an original topic rather than "piggy-back" on another thread that is already underway. To answer your question, "Lack of quality of service" sounds like a good start (or a good ending), but it is not a sentence. Improve it and repost it where it belongs.