It's interesting these comments, the guy I bought my car off said he only used v power, he also said on a long motorway run he would get 30-32 to the gallon. The Shell in Lincoln is a bit far away so I've just been using Esso 97, I went to London at the weekend and did a fill to fill and only managed 25 and I was just cruising at 80mph on the A1 all the way there. I'm gonna run some v power and see if there's any difference but it seems related if your error code has never come back. I've just checked v power prices in Lincoln and it's less than what I'm paying for Esso so nothing to loose