I'm Rich

I've got a '96 1500 2wd with 126k on the odo. It seems (and smells) like its running rich. Its not throwing any codes, but is running a little rough sometimes. Does anyone have ideas of things to look at, try, test, etc. based on that info. I know it's not much, but any help is appreciated.
Thanks

plugs and wires, air filter, pcv valve, gas filter, and check if your egr is working right.

i have the same problem on 94 suburban 2wd already have replaced all as above egr seems to work fine now what?

plugs and wires, air filter, pcv valve, gas filter, and check if your egr is working right.

O2 sensor?

its been a long time since i changed it way before i had the engine rebuilt its always had a miss in it but it worse now. how can u check the o2 sensor?

try taking a can of carburator cleaner and spraying it all the way around the edge of the intake manifold. If it appears to smoth out at some point in this process, you may have a vacum leak around the manifold gasket. Another method is to hook up a vacum gage ($15-$30) and read the needle fluctuations. Most manuals, like Haynes will give you a chart of needle readings to help you determine if it is vacum, valve timing, ect.