Quote Originally Posted by lswing View Post
You've got a boost leak or other issues causing the bad performance when tuned. Any tune you put on the car will cause a similar issue. Tune the car and the get the issues fixed and you will be golden, and fast!
Thanks for your comment Iswing, yeah I did wonder if there were some other issues. There is a bit of play I think somewhere along the transmission line, could be propshaft, or final drive or maybe in the gearbox, I couldn't tell as am not a mechanic but just mechanically minded! But sometimes on slowing down and then speeding up again, there's a thud, where it kicks in again.

Will have to get it seen to soon.