2001 Nissan Frontier rough idle

I have a 2001 Nissan Frontier with the 3.3 L V6. Has 215,000. The truck has a pretty rough idle and a bad smell coming from the exhaust. It seems to run fine when driving, but is noticeably rough at idle. Just had a new distributor put on it. I replaced the spark plugs last week and I’m going to replace the plug wires tomorrow. It appears as though it might be running rich. I only get 200 miles out of a tank of gas. Any ideas?