I have an 05 STS, 4.6L with 85,000 miles. Had the oil changed on Black Friday (and it runes out to be a real Black Friday). Lol. Anyways I get in my car, drive approx 2 miles and hear a tapping sound. All of a sudden there's a knocking sound coming from what sounded like just forward of the end of the dash but under the engine. The car shuts down, no warning lights. I tow it to the dealer, oil is full but engine has "catastrophic engine failure". Had to put another engine it at $7200 right at Christmas time. What a bummer. Any ideas to what may have caused this? I change the oil every 4 months for 3 years without fail. I never drive more than maybe 325 miles in a month. Any help is appreciated. Thanks,