There should be a certain amount of tact involved, and I agree if I were the customer I'd feel better seeing it in writing on the repair order in case something goes wrong/situation goes from bad to worse. Something the tech should put on there would read: "Contacted Zone Tech Representative, rep requests owner tries using mid-grade fuel instead of Premium fuel as a test to see if situation improves, other zone offices reporting improvement in driveability by switching to mid grade fuel".

Gilly

wow, interesting, but what about heavy load conditions. for example, long steep hills, mountains, and 100+mph driving? i would imagine that 89 octane fuel would not be appropriate under these conditions.