Rough Idle, Rich mixture

[jetjock46]

OK here we go,
I have a 96 Sunfire with the 2.4 engine. It started out with the replacement of the water pump. Yes I replaced the water pump and then afterword it idled poorly and keeps getting worse. The code reader showed that I was not getting a response from the HO2 sensor and the EGR. I replaced both and the plugs. I also again opened up the front of the engine again to see if I skipped a tooth on the timing chain, but that seems to be good also. The code that comes up is P0172 "system adaptive fuel too rich". The plugs have a lot of carbon on them and it smell like unburnt fuel. It Idles very ruff. I looked for a vac. leak and there seems to be none. When in park I will rev the engine up and it will go up to 4000rpm and start to cut out, I assume , because of the ignition cutout. What am I missing? I can't be this difficult! I'm about ready to push it off a cliff. HELP!!!!! Thanks