1996 Avalon Engine Light problem? HELP!

[Hybrid-JD]

i currently own a 96 toyota avalon xls. its been great so far but the engine light has been on for the past couple months. i've brought it to the dealership and they've reset the sensor and what not but it still comes back. they've told me many times that its nothing but it seems to come back. FINALLY this time when i went back they told me that its my "Knock 2" sensor. Price of it was like 180 and install was another 400 Canadian. i said not i would wait for abit.

anyonw konw whats the down fall with the KNOCK 2 sensor?

anyone else have the same problem?

btw. i've also noticed after having the engine light on.i've noticed my gears haven't been changing properly. or when it does change. it seems to be very rough.. it goes to gear 4 sometimes ..but when sometimes i floor the pedal it does nothign but sit at ilke 3thousand and it just goes really slow?

HELP PLEASE!

thanks

Jimmy