SEAT Ibiza 1.2 TSI bucks under hard acceleration

[VeeFource]

Our manual 5th gen 1.2 TSI Ibiza has started to give quite a big buck about a second into hard acceleration between 1500-3500 revs, pretty much as the boost is building in fact. It's almost like the ignition is cut for half a second and feels similar to wheelspinning on a wet drain cover but happens only once.

I noticed what sounded like a boost leak the other day, whooshing sounds when the turbo comes on with reduced power. Bizarely however this seems to have disappeared again now.

VCDS is showing no fault codes oddly enough. I suspect it may be the MAF but before I start replacing things, has anyone else experienced this problem before or have any thoughts on what it could be?

Thanks in advance :-)

[1988stacey]

Sorry to hear that mate, could it be the coil packs? they don't always show fault, you had it booked in anywhere? how many miles?

[VeeFource]

It seemed to stop when disengaging the tc and esp. After driving for a while with those off it seems to have stopped doing it with them on now. Can only put it down to rotating the tyres and the car having to learn the new setup But at least it seems to be running fine now

[1988stacey]

Is the tyres on the front the same make and tread depth on the front?

[VeeFource]

Nope, they're nasty ditch finders from the previous owner. I replaced the ones on the front which were more worn and then ended up rotating them so I could wear out the remaining ditch finders more quickly which still have a fair amount of grip left on them. Looking back I should have realised this might have upset things sooner as the steering was slightly off after the change around.

That said it only started doing the bucking thing after those really dry few weeks came to an end so that didn't help with twigging the issue.

I was sure the car had tyre monitoring but couldn't find a reset button anywhere (my old FR had one anyway). In which case I guess the car just has to learn the new tyres over time