Different. "Here I go" refers to yourself only. "Here we go" usually refers to you and another person. However this depends on the context. For "we" can also mean "I"! This is the royal "we". In this case your expression has a haughty and sneering attitude to the one you are addressing.

Well, the expressions are slightly different. If I were to serve you something, I would say to you, "Here you go". If we were, for example, riding on a roller coaster together, at the start of the ride, I might say, "Here we go". The difference is just in perspective.