2011 WRX. Replaced the fuel pump, plugs, and turbo but still losing power at wide open throttle. If I let up on the pedal, it regains some of the power and will at least accelerate. It presents as a timing issue. Previous owner installed Cobb S2 and I have the AP for it but I don't know enough about them to use it like I'm sure it could be. Anyone else have this issue? I really don't want to replace a timing chain.