This is only an (slightly)educated guess at the moment, but my car is occasionally going into limp mode when under sustained boost (e.g., 3rd or 4th gear from middle rpms upwards). The turbo isn't stock and can handle way more boost than is being asked of it (it's gt1749vb). As said turbo is only 15k miles old, I can only assume the issue must be a request not met rather than anything like sticky vanes.

Question is, knowing the turbo is within the operational limits, would the occasional limp mode be indicative of damage being caused somewhere? Or can anyone else think of a probable alternative issue?

FYI, if the car is revved from say 3.5krpm upwards, it'll happily fly through the gears without any problems whatsoever and it only going into limp mode very occasionally when accelerating from lower rpms (maybe 1 in 10 to 15 times?).

I will scan for codes at some point too and these will obviously give a definitive answer to the limp mode, but thought I'd ask in the mean time.

Cheers

slight vacuum leak maybe? When starting from lower revs has your foot been on the brake / queuing in traffic?

Sounds like its making too much boost too quickly. At lower revs the extra boost has nowhere to go and the ecu goes into panic thinking the engine might be near to death.

has it been mapped for this turbo???