Dodge Repair: 88 Dodge 360 runs rich

Question
1988 dodge 360 tbi 1 ton motor home. The engine runs rich. <50,000kms. AIR system disconnected by previous owner. New plugs installed old ones were nice tan colour. a friend following me when driving notes rich smell. tail pipe has black soot. Is there a performance chip or prom available to rectify the problem, increase performance/mpg ?? Thanks in advance (retired GM technician in Nova Scotia)

Answer
Hi Brent,
Please tell me if there is another size (in L) for that engine so I might more likely find a section in my many manuals that pertains to it. I have car manuals from the 80's, but not truck manuals. But that engine could have been also used in a rear wheel drive car.
My first thought is to see whether it does have self-diagnostic capability to tell you a fault code number which would be in the OBD-I system of codes. You would find out by turning the ignition switch on-off-on-off-on and leave on, doing that in 5 seconds or less elapsed time. The check engine light should remain "on" and then it should start to flash, pause, flash, etc.
Count the number of flashes before each pause. Repeat the process for accuracy. Then let me know.
What is the AIR system that was removed and why, if you know.
Roland