Isuzu Rodeo 2004 check engine light

Isuzu RodeoMy check engine light is on. I took it in and had spark plugs changed and ignition coil light still on took in again. I was told I needed a catalytic converter. Light is still on and my mechanic doesn’t know where the problem is can you help me

Just post the check engine light codes below and I will assist you with your problem.