Unit94Z28

So I have a 94 Camaro (LT1) and the SES light is intermittent. So heres how it works...when the car is not at running temperature/colder, the SES light will not come on. However, once it gets there...the SES light comes on and then the high fans come on (I can hear them when im going 60 on the highway) Also when I come to a stop light and it idles for a couple seconds the fans and SES light shut off, but the second I start moving and air starts coming in the SES and fans come back on. The car idles and drives just fine with no power loss at all. I have trouble codes 29, 32 and dreadful 36 I know that usually that means the opti is bad (number 36) but...here are my questions

A) If the opti is "bad" then shouldnt the motor misfire or lose power?
B) If the opti is "bad" but I dont notice any difference aside from the fans and SES light coming on earlier (and staying on) couldnt I just get a manual fan switch and override them and save my self from buying a $250-$850 opti?

ANY ideas would be greatly appreciated Thanks to everyone who helps!