Check engine light NOT on....

Hi all. I new to the website & forums. I have a 2001 black S-Runner with 328,000+ miles on it(I work an hour away from home). Just failed inspection with trouble codes P0141, P0171, & P0420. I went through this 2 years ago, and had both cats changed, as well as the downstream O2 sensor. I am figuring that the cats are still OK, as they are typically good for 60-80K miles, right? I have put 51K on the truck since the last inspection. I am suspecting that the upstream O2 sensor is done, as it appears to be the common denominator between all three codes, and it may in fact be original to the truck. Also have been noticing that the truck appears to hesitate during acceleration, and I read that one or more of these trouble codes could indicate a fuel injection problem. How off base am I here? Also, my check engine light DOESN'T illuminate, as it should. I checked my fuses today(under the hood & under the dash), and those that would appear to affect the MIL(IGN, EFI, etc) all seem good. Now I'm thinking maybe the bulb is burned out. Am I biting off more than I can chew trying to replace this bulb? How involved is it to try to get at the dash board lights? Have I overlooked some other cause? It would be a real hassle to take the dash apart only to find that the bulb is fine. Even if I get the exhaust system legal, an unlit check engine light will still fail me. Any help you all could lend would be most appreciated. Thanks. God bless. Seth

 

Removing dash is quite easy.
Suggestion: if you replacing one bulb replace all of them.
O2 sensor: test it first.

 

I had a 1997 that drop 2 MPG. I would save receipts from fuel up and reset odometer to watch this. Suspected something was wrong and bought a ultra-gauge and low and behold it was throwing a O2 sensor bank 1 bad. Replaced censor no code and mileage up 2 mpg. Auto-zone has a code reader that they will hook up for free but ultra-gauge is pretty cheap.

I think my CEL was intentionally disconnected I don't know after you have posted this maybe burnt out?

Not a helpful post but thought I would share.