Rear Door Lock

My 1993 Mitsubishi Expo LRV does this off and on also. Sometimes I kick it with a karate kick (doesn't help much). It usually happens when I have a bunch of groceries in the back trunk. I think we have to go to a locksmith. I think it is a spring in the handle, but maybe more than that. Also the hood doesn't want to lock shut all the way down in hot weather, only in cold weather (sometimes). I was told that is a spring too. Also the gas latch sometimes doesn't want to come open in the cold weather sometimes...it freezes shut. Usually when the tank is near empty. I heard Mitsubishi have a lot of little problems. Mine eats oil now too. At least I get good gas milage. And a lot of storage room when the hatch lid opens. P.S. Dealer said it needs a new latch. Maybe about $170 or so? I forget the exact amount.