At least 50+% of the bad Lean Burn rap comes from points-era mechanics that refused to learn anything new, so they just threw parts and blamed their inability to diagnose a problem on "those damn computers".
That said, there were real issues... Computers were slow back then, and they had trouble keeping up with driver and sensor inputs. Sensors and actuators were both vacuum and electro-mechanical. These pieces are not robust to begin with, compound that issue with early O2 sensors and widely varying fuel quality. Gasket technology wasn't as good, and when vacuum leaks developed, "Lean Burn" wasn't easily made rich with the turn of a screwdriver.
Thus other than the aforementioned slow processing speed, computers were rarely the issue. Eventually "Lean Burn" became more reliable, and just as Aspen morphed into Diplomat and became beloved, Lean Burn became became Electronic Spark Control and lived until 1989 on V8 cars. I still see 5th Avenues in daily use, and their owners look like they barely know how to install gasoline into the tank, let alone "convert" the ignition system. I just drove an all-original '88 5th daily through the winter of 2014 and probably only opened the hood to top off washer fluid.
Chrysler, through it's experience in space-race electronics (Huntsville, AL) tried to do what no one else back then could do... Clean-up emissions by controlling fuel and spark based on sensor inputs, then run the whole thing on algorithms vs. a bunch of hang-on devices like catalytic convertors. Just like 2016. In '76, LB cars were clean enough to do without cats. But this was bleeding edge tech back then, and the hardware and techs were most definitely not up to the task. They apparently didn't learn **** from the experience, because by 1980, they were back at it with "Electronic Fuel Management" (1981-83 Imperial).
