AC quit working at low rpms, so I put her on the lift and checked the low side pressure. It was too high. I know that metering valve on the compressor can fail and cause this also, but not wanting to chance trying to repair a compressor with 140K miles on it,I ordered a new 4 seasons for 213 bucks from PartsGeek. We'll see. The wife will be very happy if I can get it going.