I am doing a complete tune up to my uncles truck. When I first picked up his 1996 Toyota T-100 it had a bad miss. So I did the basic spark plugs, wires, fuel filter. That didn't make it go away so I went out and got a coil pack. Still nothing, could this be a cat or O2 sensor? It also throws the check engine light but I don't have code reader for it. Any suggestions is appreciated Thank you.

Miss fixed. Thanks for all the suggestions and replies they really helped me. I don't think I could have done it without ya'll.