About 3 months ago, I noticed my Forester doesn't accelerate and pull like it used to. There is a slight incline in the road on my way to work and it actually loses MPH with it floored going up it. Pulls good to 3-4k RPM then wheezes out after 4500 RPM. Even the exhaust tone is quieter. (I have a Magnaflow) Cleaned the MAF sensor, changed the pre cat O2, reset the EMC, cleaned the throttle body, and ran both Seafoam and Techron in the gas tank. Doesn't use any oil/coolant. No CEL or stored codes. MPG hasn't changed. Idles and runs very smooth. Anyone ever run into this? Is it possible the AVLS is not kicking in?