had this problem with losing coolant so i had an egr delete kit installed and all new inj. after the install i now lose more coolant than before about a 1/2 gal a week but i do not know where it goes nothing on the ground and i also replaced the coolant tank cap. i took it back to the shop i had it done at and they did a pressure test on the coolant tank and he said it was good that its not losing pressure. im going nuts over here as this is my daily driver and work truck.
also out of the blue my ac or heat wont work it just goes blank and i cant turn it on for about a day or two but then it will come back on and work fine