96 accord A/C problem..need help

[57ringo]

Hi,
I'm working on my girlfirends 96 honda Accord v6. She has owned this since 98 with now a/c problem before and last week said the a/c wasn't cooling good. I put my guages on it and the low side was around 30 and high side went from 180-350, back and forth in about 4 seconds. At times went to 450 and either killed the engine at idle a few times or the pressure switch kick off. The fans are running, the condensor & radiator are clean. I changed expansion valve & drier, sucked it down and put less than 2 12oz cans in. The system calls for a little over 21 oz R134. The high side still varies like before. I ran water on the condensor and it brought the pressure down but still varies up and down. I talked to a Honda tech at a dealer and he said the compressor could be the problem. Do you have any ideas? I cut the old drier open and it looked very clean. When I replaced the drier and valve, the lines looked clean.
Do you have any ideas,I am stumped.

Thanks,
Pat

[57ringo]

I've had a couple guys tell me it's the compressor. Does anyone have a good used one that will work? This is a v6 car.