Update:
I've now put 2 tanks of Tesco 99 in, but the issue continues.
It's been into VW who have ensured that the onboard software is correct and up to date; having explained the problems I've been having they also checked for stored fault codes and then printed out and showed me a complete system check - according to the computer, everything is fine.
The symptoms as I see them are:
- Intermittence performance - the car is mostly consistent but then sometimes flies down the road like a scolded cat, which highlights the fact that there's a problem.
- Poor mpg - over time, I've been seeing 21mpg for a journey that would normally be 27-29mpg.
- Jerky throttle response - about 50% of the time, releasing the throttle feels like I'm gently pressing the brake at the same time
- Lumpy idle - The rev counter doesn't move, but on some occasions when stationary, the car feels like it's missing beats
VW's position is that because the computer doesn't recognise a fault, they won't suggest doing anything, which is fair enough, but that basically leaves me having to decide what's wrong and then getting it done in the hope that it's the right thing. No pressure.
Switching fuel (whether it be to 97, VPower or Tesco 99) seems to calm the symptoms down for a short while (I presume because the ECU is adjusting?), but then the car settles back down into being weird. If anyone has any ideas, I would appreciate it.
