[justme1969]

But if you get too High of final drive ratio for engine optimum torque curve then you will have a constantly loaded engine.
The engine management system wont be happy untill it hits a preprogrammed PV value to do its thing closing valves and adjusting fuel air mixtures etc.
For ya old schoolers the vaccume would remain too high to close egr etc.
This changes for nearly every application and even sometime per car.
An effect of this many people notice is from a restricted exhaust.
Where the engine controls will attempt to lean out the system to correct for a abnormally rich system.
It effectivly causes persons foot to go further into go pedal and resulting in ever richening system till key is shut off or computers give up trying to correct for the probblem placing system into a limp mode or clear flood fuel mode.
Where upon you see check engine or call tow truck LOL.
waiting 15 minutes or so will usually allow you to limp home if you dont try to make it run like there is no probblems again.
OK sorry so long I wanted everyone to understand without giving me 200 corrections about specifics.