My 2006, 35,000 mile vrs is 'missing' under load / boost. It started doing it back in the cold weather, and has continued since.

It's like carbuerettor ice, in as much as I get power, then it misfires until I back off the accelerator and drive it under light load. I wonder if it could be a gummed up fuel filter, as I think it's still the original one on the car, or more likely a sticky injector, as it's as if a cylinder isn't firing from time to time, in a Diesel I'm guessing it's insufficient fuel going in. It's worst between 1500 and 3K RPM.

I haven't put any system cleaner etc. through it yet, but this might be the first port of call.

The headgasket seems to be OK, (Coolant level unchanged, oil filler cap clean)

Oh yeah, no fault codes either (I've had the 'emmissions' light a couple of times, about 3 - 4 months ago, but nothing recently)

i you had a blocked fuel filter, the problem would occur all the time under load, as there wouldn't be enough fuel going through, wouldn't do any harm to change it, but i wouldn't expect changing it would cure your problem

i you had a blocked fuel filter, the problem would occur all the time under load, as there wouldn't be enough fuel going through, wouldn't do any harm to change it, but i wouldn't expect changing it would cure your problem

It only happens under load, and it happens nearly all the time under load, right across the rev range, in as many gears as it is legal and prudent to check on the public highway, but it's not like it's dropping a cylinder constantly, it is hesitant and jerky, full power, less than full power, full power, less than full, almost as quickly as you read it there.

Backing off stops the problem, there is no evidence of any hesitancy at idle. Backing off forever is not an acceptable solution.

Disconnected the MAF and took a short drive, no difference.

No smoke (Well, no obvious black clag anyway, so whatever it's getting, it's burning)

It only happens under load, and it happens nearly all the time under load, right across the rev range, in as many gears as it is legal and prudent to check on the public highway, but it's not like it's dropping a cylinder constantly, it is hesitant and jerky, full power, less than full power, full power, less than full, almost as quickly as you read it there.

Backing off stops the problem, there is no evidence of any hesitancy at idle. Backing off forever is not an acceptable solution.

Disconnected the MAF and took a short drive, no difference.

No smoke (Well, no obvious black clag anyway, so whatever it's getting, it's burning)

put a filter on it, you may have gotten some dodgy dirty fuel through

Sounds like the symptoms mine had - mine was diagnosed as a 'collapsed fuel filter', a new one cured it straight away.

Credit to my local dealer for picking it up as well, my local VAG indy missed it.........

Edited 6 April, 201016 yr by KR MAN

New fuel filter has seemingly sorted the problem. Sweet as a nut this AM at 3 degrees C (Was always worse when cold)