we have tried everything, thermostate, heater core, sensors, nothing is working, any suggestions? please reply, we live in chicago, we need heat

When your engine is warmed up doe's both heater hose get equaly hot? I had the same prob when i bought mine , and the hose from the engine to the heater core was somewhat hot but the one going to the radiator was almost cold.After replacing many parts like you did , I found out that the hole on the engine were the hose connect was almost block with residu. Leaving just a small amount of hot water going to the heater core. After cleaning out the hole i had all kind of heat ..... I ve got the 4.3 lt and the hose has a quick disconect to the engine. Might be a bit different on yours, hope this help.