Isuzu Npr77

Dear Sir/Madam,I am writting in order to ask for professional advice about my Isuzu NPR 77, construction year 2006.I hope that my letter will be received by the right person which would be able to offer me professional help about a truck Isuzu NPR 77 construction year 2006,which i bought 3 months ago. I bought Isuzu NPR 77 because its characteristics were the most suitable for the needs of my private company. My company posseses several trucks, MAN and Mercedes Benz,which have bigger transport capacity, and which we needed for purposes of our company. When we came to buying a smaller truck,we decided for Isuzu NPR 77 because it was the best by its characteristics for the local transport of merchandise.We have the problem with engine power which delivers less power than it should. The engine starts and works perfectly,but hasnt got power and acceleration. In the last 2 months we have been asking for help in various authorised services across Serbia and Bulgaria. We have repaired the turbo charger and,on their advice,we also changed the air flow meter,which we barrely found in Spain and waited over 20 days for delivery. The truck still hasnt god power. In service they say that engine has good parameters. I hope you will give us advice how to solve this problem.Yours sincerely,Milos JovanovicSerbiae-mail: