Recently my A/C hasn't been cooling as well, and it seems the compressor's cycling pretty frequently. I know the FAQ has an extensive list of possibilities, but I'm wondering if anyone else has had these symptoms:

Frequent compressor cycling, even at highway speeds (can feel engaging/disengaging)

more compressor noise (a whirring sound when engaged - it's always been there, but is now more pronounced) at lower speeds.

I'm not sure if I trust the cheapo low-side gague I got with the can of 134a - when I attach it to the port, it will go into 'overcharged' when compressor stops, and then back down to 'normal' or 'high' when compressor kicks in.

Can I risk adding more refrigerant (even a little) to this system, or is that potentially unsafe?

I should add that I lost a bit of gas/dye/oil when I attached the gague, and since then the compressor has been noisier, so that info is pushing me towards adding some.

sorry for the long post - just trying to hold out 'til the Fall weather! Any advice appreciated!