EZGO II Sport Power loss

[Topdog60]

I have an EZGO II Sport. Not sure of the year but it is 3 or 4 years old. The problem I have is with the power. When I start to drive the cart it hesitates and will pop or backfire a few times before it moves. Sometimes it will pop or backfire when it first strarts to move. It also has very little power. It may start to run like normal then it just slows down. Sometimes it will jump back and forth between the 2 stages and other times it will surge then slow down then surge and back. When I start up the drive, up hill, regardless whether it is moving fast or slow it will come close to a complete stop. I haven't actually stalled completely yet but have come very close several times. Does anyone have any ideas and is it something I can fix myself. I had the cart serviced about 2 years ago for the same problem and the tech said that because I was not running the cart longer and harder that it was affecting something. I could not remember what he said but when I ask him about it now he said he would have to look at it. Since I am unemployed at present I don't have the means to have it serviced. Any help will be appreciated.

Cal