VegasBuilt

My 93 sc400 is running smoothly and sounds in great condition. There is a loss of power when I accelerate and the cats I just installed are new but they still glow orangr-red and there is no power when I try to drive. I researched to try and narrow the problem and it's telling me either a fuel injector is bad, my cap and rotors or sparkplugs aren't gapped correctly. There are two other problems listed but it says you'd notice the sound and vibration of the engine if it were those. Does anyone know about my problem or has had the same issue and fixed it?? I don't want to just change it all and still have the same issue.