I'm assuming there aren't any underlying issues (food allergies, ADD or whatnot).
That being said, when my son has a fit (he's 3) I say, "Jacob I cannot understand you when you talk that way. I will listen when you are ready to talk nicely." Then, I walk away. The lack of an audience works wonders. If he wants to throw himself on the floor and cry, so be it. I won't give it any attention.
When he reaches the point of being unreachable, I will get down with him on the floor and tell him he needs to relax. I tell him we will count to three and take a deep breath. I take an exaggerated deep breath and exhale heavily and by the third time doing it, he's done crying and doing it with me. Then, we go on with life.
As for the time-out issue, I think it's a control thing. I think your son figures if he makes them hard on you (kicking, saying rude things) then you will give in and not make him do them. Pretty smart, actually. Lol. If that were our son, I'd either ignore him completely and go on with life as if he isn't even there. OR you can tell him the timer starts over every time he screams/yells or says rude things. At 4, he has a better concept of time, I'm sure. And, if you have an actual timer that buzzes, he will learn quickly that a reset of that postpones getting out of time-out.