92 Astro AWD Engine Hesitates, lack of power

[Inssomniak]

200hp "W" engine

Idles perfect, starts perfectly. In idle if you stomp on the gas it will hesitate, and backfire occasionally. Lack of most power while driving, I cant determine if its a bad Cat or a bad map sensor/throttle position sensor. Any way to check these? 250k kilometers on engine. Seems to run lean. EGR code pops up if I do the diagnostic check, as well as a TPS code, I have check the EGR, it moves freely. A clogged cat converter cause too much backpressure resulting in the backfiring, and lack of power? Bad map sensor or TPS cause this?

Thanks.!