Last oil change back in October, I put M1 ESP 5W30 in. I underfilled slightly (3.5 vs 3.7qt) to make it easier to track a rising oil level on the dipstick. I then turned off ECON mode and started using 91 octane exclusively. So far, through the winter and into spring (6 months and 2600 miles of mostly short-tripping) the oil has not moved up on the dipstick at all. Not sure how much to attribute to ECON being off and how much to attribute to the higher octane fuel, but one or both of those seem to be doing the trick. Last spring, using 87 octane and leaving ECON on all the time, I could easily see rising oil levels on the dipstick despite warm weather and a ~2000 mile road trip. Honestly, I figured 2000 highway miles in less than 2 weeks was the perfect scenario for no fuel dilution, yet I saw the oil level climb on the dipstick significantly during that trip. Anyone else have success stories with combating fuel dilution? What did you do?