1993 camry LE 4cyl.

what does this gizmo do that is located in the air filter cover?

what symtoms if it goes bad or is aged??

 

The sensor tells the computer what temp the intake air is to the engine. The computer uses this info to set the air/fuel ratio.

If the sensor fails the computer will set default mode temp of 68F.

If the air temps are higher or lower then this default setting the mixture will not be correct.