My boyfriend and I have been together for 4 years, and somehow he still lies to me, makes empty promises, and not understand my feelings. When he's upset, he would make up these crazy excuses why, instead of just telling me up front what it's really about. I usually know when he's mad, (especially when he is often calm), so it frustrates me more when I already know what he's mad about and won't say. However, when I'm upset, he is well aware of what upsets me, and he remains oblivious and clueless about it, which makes zero sense since he does the same old crap every time. When we talk, he would start saying one thing, and contradict himself in a later sentence. When I call him out on it, he tries to change the whole situation, as if I'm the crazy one. After a while, I've developed a short temper and a low tolerance for him, but I still love him. I want to be able to express myself to him without having to deal with whatever nonsense he might pull... How will I be able to manage, if possible?

People have behavior patterns and it sounds like he has developed his and isn't willing to improve that pattern. You may still love him but are you willing to tolerate this long term? Personally speaking I can't stand dishonesty. Your best approach is communicate all these frustrations to him during a good time when you all are communicating well. Then you have a decision to make. Move forward with your life or be stuck in that one. Sounds like you might deserve better, even though you do love him.

He may need some help, like a therapist.

Sounds like you BOTH need some practice in communicating instead of arguing or triggering each other -- with one or both of you being angry, defensive, or withdrawn and the other on the attack. When he makes excuses about why he's upset instead of being upfront about it, it's because he doesn't want to have conflict with you (and he believes dealing with his upset will stir up trouble).
You're also making a mistake a lot of people make "I know he knows what's bothering me he's just so oblivious about it" ---In actuality - he might NOT really understand your feelings or point of view! Women often think guys should just "know" -- but they don't and are often clueless even if you've told him a billion other times, he might be shutting down on you to avoid conflict. It's your job to explain it clearly and without a lot of heightened emotions and accusations so he can take it in and process it. Don't allow him to be responsible for your emotions - you be responsible for them. That way he can't make you so crazy frustrated and you can take charge so express how you feel. Sounds like you're wanting him to CHANGE a lot of things about how he behaves and how he acts. Double check your expectations; is there any area where YOU need to let go and let him be who he is? Are you trying to change him instead of learn about why he's acting the way he does? Does he have a real problem that he needs help with? You can't deal effectively with anything if you're upset or emotionally reactive... finding ways to communicate (and LISTEN) can improve these scenarios where you do all the talking and he does all the excuse making, blinking and not doing anything about it.