Yer thats what i dont understand. Its still making 15psi but not making the power at the wheels. Could it be a drivetrain issue as every now and then i get a strange resinating noise like through the rear beam, i've neve heard anything like it. Im no expert so havent got a clue. I got my mechanic looking at it next week but it would be nice to have an idea of the problem.

As big steve said when it was on the rollers it sounded spot on and sounded like it was 260easy