[hellosailor]

"The fact that it shuts off when you turn your thermostat up to 5 rules out a relay in my opinion, after all, it did shut off."
Good point!

That does sound more like "I just can't keep up" which could be slight refrigerant loss, etc. One quick way to test for that would be to load in some block ice or dry ice to provide extra cooling, and then try again with the thermostat set down cold. If it cycles and works properly that way--then the gas loss would be very likely. Or, more/new insulation, but either way you'd need to check the gas charge or check for leakage. The simplest way to test for gas leakage is to spray all the fittings with bubble-soap, and then look to see if anything is blowing bubbles. That would only show a fairly large leak though. A "sniffer", for less than $100 used from eBay or a pawn shop, is way more sensitive (will pick up leaks that are less than 1 oz. of refrigerant per year) but costs a bit more up front, and requires some patience to work with. An essential tool for DIY refrigeration/AC maintenance though.