Oxygen sensor problems
 

2002 Silverado 1500 LS 4.8L 200k+ miles

Check engine light came on and codes are showing low circuit input on all four oxygen sensors. The "suggested" maintenece from autozone was to change the fuses. I pulled both fuses and niether are blown. So i crawled under my truck and checked all four sensors. They were all tight and wiring looked good. There was no damage or chaffing to wires that i could see and all connections were plugged in and secured. Could the problem still be the fuses, even though they are not blown? Or should i just go ahead and change all four of the oxygen sensors, or at least take them off and try cleaning them?

I would appreciate the help, thanks.

Before I did anything else, I would check all of the fuses.

So check all the other fuses other than the O2 sensor fuses? Just want to make sure thats what you are meaning because i have checked the two O2 sensor fuses and they are not blown. Can fuses still start to go bad and cause problems even though it is not blown?

Sometimes fuses control things that they are not marked for. Normally a fuse is either good or bad. No in between.