I just replaced the catalytic converters and did tune up still no power

1995 has limited diagnostics. Someone who knows how to monitor that computer system and perform some tests with labscope, etc. needs to diagnose this car. Unfortunately you are now beyond guessing. You've done the basics like a Compression test when you did plugs or fuel pressure test ? Don't know history of car like why did you do converters? Did it need them? A good qualified shop is your next step. Expect to pay $200-$300 at least to diagnose