my air govener isnt always shutting off at 120 and its suspossed to be preset, i have replaced it twice and the same problem keeps happening. my air dryer isnt hooked up so it doesnt blow off pressure. it sometimes builds to 130 to 140 and blows off an air line. i was wondering if its in my compressor or if its possible that trash is stopping something up. i have a big cam cummins if it helps any.