My 2002 chevy trailblazer keeps loosing power in the gas petal?

There are a few things, first is the check engine light on? Possible causes, fuel pressure, the gas pedal itself as this is a drive by wire set-up, the Throttle Positioning Sensor, a plugged catalytic converter.

How would you know if it's the catalytic converter?? What can cause the fuel pressure to be too cool or high?? I just replaced the throttle body, so how can it be the throttle sensor My check engine light has always been on, but when I had it checked, the only code for it was dealing with coolant fan, (never had a problem with the temperature level)

I don't know these things, so I have to ask. To check the cat drive it and get it hot, park in a dark area with the engine still running, the cat would be glowing orange if it is plugged up. Also with the check engine light on all the time you don't know if you have another new code. I would suggest having it scanned and write down the codes in-case we need them to fix your problem. If you replaced the throttle body then the TPS is new also. But on these years the plugin to the TPS, the wires brake internally. At least where I live when I buy a TPS it comes with a new plugin. So we have to start somewhere. Fuel pressure is easy to check, just need a fuel pressure gauge.

Ok I'm gone go have it put on a machine & let you know what it says