94 Grand Am lacks power

1994 Grand Am 2.3L Automatic 157,500 miles (20,000) rebuilt engine. Rough idle and lacks power. Check engine light is Not on. Changed or tried, fuel filter, plugs, coils, ICM, crank position sensor, ECM, several vac lines. Cleaned injectors tonight and after 3 mile test drive, noticed CAT is glowing red. Problem developed gradually over a couple days. Trying to decide what to do next. Thanks in advance for any help!

Cat is bad. Replace the cat, and make sure the car is not running rich.

I agree the cat should not be glowing and be any color other than metallic.

Many thanks from a newbie! I'll give the cat a shot.

you may want to look at your muffler if the cat is backed up and you have a stock muffler i would want to look at it