Hi, I use to have the 940 2 ltr. Wentworth saloon but it was 1991 the engine layout will be the same. It was a mitsubishi turbo, which is the one that spools up pretty quick, yours should be identical. The first place you should start is to see if the wastegate rod, which as you look at your turbo is underneath it, is attached to the wastegate lever,a clevis pin keeps the rod in place. Sometimes this pin rusts and falls off then the rod will come away or the whole assembly with wastegate lever can seize with rust.Just make sure the rods connected and the assemby is free to move left to right if it doesn`t loosen it up with some penetrating oil.You may be able to see this proper from underneath the car or use a mirror under the turbo.If this is all OK you can then go on to check all the hoses which supply the compressed air to the intercooler and on to the throttle assemby.They of course must have no holes and be secured properly with tightened jubilee clips.There is a metal cover on the side of the turbo ,which you can see full on, which is held by three bolts, make sure these are tight as there is a blow off valve underneath it which may leak and let your pressure go, you could dismantle this and clean it and make sure it is not torn or damaged. Just make sure the other vacuum tube is connected to the block by the throttle plate and is clear. Check that the actual turbo wheel with the fins on is free to move inside the turbo,you can see this with the top hose removed. Regards