With my ED30, it feels like all the power moves to the top end. On a good day there's responsive torque everywhere, even off boost. On a bad day, it can't pull the skin off a rice pudding below 3000rpm and feels really heavy and reluctant to get moving.
I've checked everything. Binding brakes, flat tyres, boost leaks, PCV, DV, data logging.....everything.
A new ECU that's never been flashed is my next port of call, but the faff of coding my key to it is putting me off.
One thing I and Muff1991 have noticed is the performance improves as the weather gets warmer! Should be the other way round with turbo engines