Drop in fuel mileage with 15k oil change

[Vdubboys81]

Hey guys and gals!

Just wondering if anyone has had a similar issue.

So the Polo has two fuel consumption readouts, (1 & 2). The 1 I reset every tank of petrol, the 2 has not been touched since we bought it. Before the recent 15k service, the overall average for 15k Kms was 6.1L/100km. But now, as we switched to Liqui Moly Top Tec 4200 5W30, in the last 2k Kms the average of #2 (the one I don't reset) has jumped to 7.4L/100km, which in that short amount of time is significant, and slightly worriesome. Has anyone else had a similar issue when either having the 15k service or when changing brand of oil? After doing the math, if its because of the oil, it would be cheaper to have the oil changed and go back to Castrol, in exchange for that extra litre. Any opinions or advice? Or is there something else that could be wrong (if you have had the same situation or know of an issue)? I used Shell V Power for about the first 9500 Kms then switched to BP Ultimate which I noticed actually produced lower petrol consumption and a bit more go. Any help would be greatly appreciated!

Thanks guys

[vdubmotorworx]

Did the service get done at a dealership? They might have done a service campaign on the car while it was in the shop. They should have informed you about it, but they could have forgot?. Other than that nothing should have changed when carrying out the 15k..... The car has a "running in oil" from factory so is different from normal service spec until first 15k....