has anyone else had issues regarding their turbos , not sure if i have a problem but when towing my 2 ton van up any decline the patrol power just dies a slow death, some declines lucky to get above 60kph , and while powering up the hill if i release the acc and put my foot back down i can hear the turbo spinning as if it is in neuatral and not giving any extra power, do i need a new turbo or is there a way to test them. thankful to any replys on this problem