ok. the van has just been fitted with second hand engine. it revs upto 4000 fine when stationary. however on road it is "flat as a pancake" with a lack of boost. we have a similar vehicle in at same time, and that one runs fine. checked that the vaccum pipes to boost sensor and waste gate solenoid are intact and on the correct way. have cleaned the egr fitting pipes. swapped over good airflow meter, egr valve, boost valve, turbo solenoid from donor van. still no effect. the air flow reading at max is about 350kg. the boost reading hits about 1800 when rev hard when stationary. no vaccum leaks. intercooler is clear and turbo is one month old. what could it be??