IM guessing a boost leak, or maybe a injector leaking.
I had a boost leak on my car, was running and starting ok, but lost a lot of power.
My way of testing is to take the maf off, and make a wooden disc with a air hose fitting, use a air compressor with a regulator, turn the regulator all the way down, connect the air line up and slowly raise the air pressure til you can hear it slightly puffing into the engine. Any leaks will be a clear hissing, or a loose hose clip can cause a large pop as it blows right off. Mine was a rubber IC hose has rubbed thru on the battery clamp hook.