I usually run Motorcraft 5w20 in my Mustang GT 4.6l engine. I’ve tried Valvoline blend, but usually stick with Motorcraft. Well I decided to do the Mobil Oil rebate thing (which I still haven’t received) and purchased Mobil Super Synthetic 5w20. Could it be that it is in my head that my engine sounds different? I’m not going to say bad, but just little sounds here and there that I’ve never heard coming from engine before I used Mobil Oil. Or is there actually something that is in the Motorcraft oil that quiets my engine in a way that Mobil Super Synth doesn’t?