Last summer my ac crapped out. I got it refilled and it lasted a good few months before it was blowing hot air again. When I got it rechecked this summer, the shop said that the leak was coming from the evaporator behind the firewall.
Assuming my problem was a leak, I bought a at home recharge kit. When I took a measurement of the low side line, it was reading about 75psi when not running, but when it was running, the pressure would raise to 45 psi then the compressor would shut off, lowering the pressure to something like 10-15psi, then it would shoot back up and then down, etc...
Would a leak cause this or is this something different?