Hi, as the title reads my vrs 2.0 tfsi has lost power, it just feels like it has no pull, almost like a non turbo 2.0. I've owned the car since October and it's been great, then I fitted a blue spark tuning box, this really made the car more responsive, it went really well, lots of boost. Then one day the pull just disappeared! There are no warning lights and no faults stored! When I bought the car I did the dv, fuel pump cam follower and found the pcv had a delete plate fitted, so all good. All from the good advice on this forum! I've done actuator tests on various components, the evap valve is working as it should,the vacuum unit on the turbo is clicking away nicely. The car is running well, no misfires or bad idle. I even checked the actuator rod on the wastegate as some of these have snapped on other models. I keep thinking of air mass meter, I just don't like replacing parts on the off chance it will work! The other thing was a 6.6 bar fuel filter, but doubt this would cause loss of power. Hope someone can help! 

I have sent the bluespark box back for a refund so I can concentrate on getting the car sorted, it had a 28 day money back guarantee.