Hi guys I need a bit of advice because it's annoying me now. My car has recently developed a 'judder/lurch/struggle' when reaching boost in high gears. (If that makes sense?) I'll set the scene: Just entered a motorway from the slip road doing about 60mph and cruising in 6th (approx 1600-1800rpm), coming up behind a lorry and nothing behind me for miles so I go for a gentle overtake staying in 6th and slowly put my foot down increasing to about 70mph (nearing 2000rpm) and the car will 'judder/shake' preparing to boost and then pull hard. However, if I where to knock it down into 5th or 4th and plant my foot down it would just pull like a train all the way to 3500-4000rpm.

The car:
- Vectra 1.9 CDTi (16v)
- Remapped
- EGR valve restricted both sides (not blanked)
- inlet manifold replaced 5 months or so ago (throttle body cleaned at same time)
- De-Catted
- Boost sensor cleaned nearly a year ago (thinking this might be the problem and may need replacing)??


Any help on this would be greatly appreciated because it's not just become annoying but could be dangerous

Thanks