This probably got covered so many times but I can't get the right answer. But my question is through the rpms at wide open throttle, is boost suppose to hold? Mines shoots to 6 drops to 4 sometimes 3. when it shifts shoots to 6 then drops. I have a 09 s60 SE 2.5f fwd a/t with 66k. eurosporttuning intake system. And just replace plugs with ngk. Could it be the tcv or cbv.