No power to engine
 

Hello, everyone. I am in a bind and hope someone can point me in the right direction.

My 2005 Chevy Cobalt went from running great to acting like it isn't getting enough fuel.

When it happened, there was a massive reduction in engine power, but I was able to make it home. No warning lights came on. Though I had the accelerator to the floor, the car would barely move.

I changed the fuel filter, fuel pump, relay and fuse. It didn't fix it.

I bought a code reader, but it says there aren't any codes. However, when I scrolled through the menu it said there was a problem with the catalytic converter and o2 sensors.

I had my dad cut the cat free thinking it would run better, but there was no change. Luckily, I haven't taken the new one out of the box yet.

Would a bad o2 sensor keep the car from getting gas even with the pedal to the floor? Is that what "running lean" means?

The car starts but immediately dies.

Thanks for your time. Any suggestions are greatly appreciated.