2003 Chevy Cavalier 03 Cavalier 3rd cylinder stop working

Engine problem
2003 Chevy Cavalier 4 cyl Front Wheel Drive Manual 120k miles

03 cavalier 120k miles manual My 3rd cylinder isn't working. I took it to a mech but he was not knowledgeable nor did he have the equipment. He did a pressure test on my exhaust but was pointless. Then he put a new fuel injector in the car, but realized that wasn't the problem. I have a new mech looking at the car, but I would like to compare what this new mech may tell me to what another mech tells me. Spark plugs replaced after the problem, and its not he fuel injectors. What do any of you think it maybe? The coil pack and/or cover? Anything else? Also I found performance wires for the 03 cavalier by Nology, but I heard they can't be put on the car.