hey showeth when I first bought my truck it was down on power and after 2 different dealers doing diagnostics that gave me bogus information, the second told me my turbo was bad because it had low boost pressure only about 8psi, they wanted to replace it for $1600. 00, so I pulled it off and took it to a very good turbo shop close to home and found out the turbo was fine but the wastegate actuator was blown and was losing air and they told me that the escaping air from the airenoid (or however you spell it) would cause a decrease in fuel as a safety precaution, because with no pressure working the actuator and opening the wastegate the boost would go beyond factory specs. , the turbo shop only charged me $60. 00 for a new actuator, I could only assume they were right in what they told me because it seem to fix it... ... ... ... .