1995 Honda Civic A/C won't work when hot outside

An unusual problem; Last fall the A/C began to "short cycle". My A/C guy suspected low R134, so he put in some gas with sealant. After charging, the engine would bog down and nearly stall, so he let some gas back out. The system has worked, but only if I park in the shade on hot, sunny days. If I park in the sun, the comperssor will not come on until I drive about 10 miles at highway speed. When it comes on, it short cycles, but is adequate to cool the car. If I park in the shade, the compressor starts immediately, but short cycles. Today was very hot, and the compressor shut off in stop and go traffic, and has not re-started. I'm not sure where to try next. Some folks are saying to replace the compressor/cluch, and some are saying there is a restriction. Any help will be appreciated.