Guys,
My grandson and I have been working on his older Honda making it road worthy. We recently replaced the entire exhaust system with an aftermarket system. Headers all the way to the rear. The package also eliminated the cat. There was provision on the header for the upstream O2 sensor so I went ahead and put it back in. We have also replaced plugs, cap, rotor and wires. We have now developed a miss/pop after warm up. The miss is every 10-15 seconds and may be a single or double triple then back to smooth running. It also stumbles and pop pops on normal acceleration. Not so much if you get into it however. The CEL light has not been set. How about some ideas. Thanks in advance.