Wideband

In theory, MPFI (multi-port fuel injection) can give worse cyl-cyl distribution than a carburetor. That happens if the fuel injectors are mis-matched in flow. No factory systems I know of monitor and adjust individual cylinders (maybe a Harley?). Most such implementations use exhaust temperature sensors to measure cylinder imbalance, but usually just in race engines. Some tuners approximate that with a hand-held IR thermometer (while exhaust is still hot).

To insure uniform distribution with MPFI, you must remove the injectors and flow test them. I should do that on my modern Mopars since both are >190K miles. So far I have trusted in an occasional bottle of injector cleaner (witchcraft) and very occasional fillup with Chevron to run some "Techraline" (whatever that is, just methanol?). Those MPFI injectors just seem to run forever with no problems, which I never predicted 20 years ago.