My Calibra Turbo is having trouble boosting. Having run the car for a while it seems the turbo *tries to kick in* ...at 4,000 revs starts to kangaroo / stall and then goes (in every gear). The turbo also only seems to go once... Not like before when it would spin up and then spin up again.
The engine is std (apart from a Bailey dump valve fitted last year).
Anyone tell me what to look for or change? Thanks for any advice.