MAF unplugged no cel or fault codes

[darrylrobert]

To test if my MAF was doing much of anything i unplugged it and started the car, it ran terrible but no 'check engine' light. I ran the car for 10seconds before shutting off. plugged in my scan tool and couldnt find any fault codes stored.why
How long does it take for the car to figure out there is a problem

Ive tried this test previously with unplugging the crankshaft sensor then trying to start it and got a fault code imediatly (missing signal crank)

Also ive read in the Haynes manual and a few places not to test like this, it dosnt explain why, i assume voltage spikes. As long as im not plugging thing back in while powered, i dont see any risk of voltage spikes?.