I have borrowed a friends Makita MAC2000 air compressor and am worried that I may have done something to it. I have used the compressor for three days. The first two days it ran fine, but on day three I had some issues. The compressor will run and the pressure will build at a somewhat slow rate untill it gets to 80psi. Once it reaches 80psi the pressure stops building and the compressor will just run and run. It seems like there is air leaking out from under the tank pressure gauge. Any help would great, so I don't have to buy a new air compressor that isn't even mine.