Engine Mechanical problem
2005 Ford Expedition V8 All Wheel Drive Automatic 70000 miles

I have a quick questoin. my car we have taken in several times for the spark plugs and some fuel injection problems amongst other things from it idoling and just stalling. Now we bought the suv at 56k and was told that it stil had the ford oval warranty and on top of that warranty we bought extended preium performance warranty. NOw we take the car in for the same exact thing and now they tell us it is the engine it needs to be repalced and it cost 7500bucks. they tried saying that it isn't registering the oil, so wouldn't the oil light come on? The check engine light came on just barley this morning just enough time to get to drive over there where it stalled and woulnd't even start back up. i am furiated and i am seeing what could be done, if the oil light will come on? and seen on other peoples forums that they all got the thing replaced that we did and it was something that was recalled too but ford doesn't want to replace with the proper kit what can we do