Ideas on possible A/C problem Options

[PaukST]

Whenever I'm driving while using the A/C, I'm used to it taking a fair amount of my engine power and acceleration (that mighty 7afe ) . Lately, the A/C will frequently stop compressing for a few seconds, giving me a puff of damp, smelly air (it's generally fairly humid here in SC), and removing the A/C load from the engine. Then a few seconds later it'll kick back in.
Anybody have any ideas on this? I picked up an A/C recharge kit from Autozone, but when I hooked the gauge up to the low-pressure port while running the A/C at full blast, the pressure would fluctuate between 25 and 40 psi. I decided not to add any refrigerant, since that wasn't the behavior I was expecting. Is it possible my evap core is all gunked up, or that the system might be over-charged (like if the previous owner added too much refrigerant)?