After changing my battery, spark plugs, 3 sensors, cleaned throttle body and dropped and cleaned fuel tank my TB still runs bad, like it's suffocating for air or gas...

What is your question?

I have a 2004 Chevy trailblazer LT with 215 thousand miles and it started with a dead battery. I changed battery and it still won't start. I changed spark plugs, 3 sensors, cleaned throttle body, dropped and cleaned fuel tank, changed oil and filter, changed fuel filter and filled tank with high octane fuel. I can start and drive it but it still throws a p0300 code soon as I let off accelerator and it sounds like it's suffocating for air or gas. We have checked all relays and traced vacuum lines they are all good, checked coils they are good and changed cat on it, it was clogged. What am I missing?

What makes this problem better or worse?

After I cleaned throttle body it was better except for the sounds of it suffocating.

How long has your 2004 Chevrolet Trailblazer had this problem?

Since it started with battery all together 2 months