Have A Carrier 06D with 2 electric hot gas unloaders that was replace by others last year. One unloader is disconnected, and when the other kicks in my pressures go from 210/ 60 to 150/110 on a 75 degree day. The only thing I can think of is a resticted discharge line. Others have said bad valves, but under full load the unit runs fine. It's not the hot gas by-pass has this has been tested. Any ideas?