SC93

When a critical sensor like a suspect MAF is disconnected and the car runs perfectly as opposed
to poorly when connected, what are the negative consequences??

My understanding is the ECU goes into a default mode on such a disconnect and uses
past accumulated data to run the car on " manual" so to speak, ignoring all sensor input
data. Except for maybe poorer gas mileage and safety measures like a complete shutdown
of car if it overheats (and not being able to detect 02 issues) can it be a big risk factor
to run car w/o MAF for a few weeks realizing that even though it run well, that doesn't mean
the MAF was bad since all other bad inputs are ignored.

MooJohn

If the MAF is disconnected it does not ignore all other inputs -- it just ignores the missing MAF signal and instead runs on a fixed set of values to keep the engine running.

Ali SC3

iTrader: (10)

ITs not recommended but is fine for periods of time. you will be running very rich and your oil will get contaminated quicker with gasoline. keep an eye on the dipstick if it looks dark black and thin then change your oil early, if you get too much fuel for extended periods of time you can hurt the motor.

Also the ecu does not use any past data in that mode, it is strictly off a static fuel map using the modifiers that are still working, basically it knows rpm, tps, and the various temp sensor inputs and then injects something that is safe for all loads with those values since it doesn't know the load at all. it would be safe to assume it roughly injects for the largest load with those conditions, and probably sparks with the least advance for those load conditions.
this is not good for economy but may appear as good than an engine that is running properly.

also there is no safety shut down for your car overheating anyways. you would have to turn it off either way.