AndyT

First of all the factory gauge is junk. Does it ever read 1 bar at idle ? Mine did, the fix was a new boost pressure sender. You need to run an actual boost line to a mechanical gauge to check the boost to see if you are bleeding pressure or possibly have a bad bypass valve or frequency valve. The Freq valve is easy to change and not too pricey. The wayo to test your turbos is to put the car in 3rd gear at low revs and floor it. The boost should climb to 0.8 at about 5k. The car will be laggy because you should probably be in 2nd at this time but this is the method to checking. I had very laggy turbos a long time ago. Turned out to be a leak on the hoses that connect to the intercoller. They were all mangled from the hose clamps. You could not see the damage until you took off the hose. There is an upgraded stonger hose with orange ends. They are about 400 bucks for the pair and definately recommended.