Had the codes checked at Pep Boys after the SES light came on and it looks like O2 sensors on both sides. Hard to believe sensors on both banks would give out at the same time.

Here are the codes
P0171 - System Too Rich - Bank 1
P1171 - System Too Lean - Bank 1
P0130 - Oxygen Sensor - Sensor Circuit malfunction - Bank 1 / Sensor 1
P0135 - Oxygen Sensor - Heater Bank 1 / Sensor 1
P0139 - Oxygen Sensor - Circuit Slow Response - Bank 1 / Sensor 2

P0150 - Oxygen Sensor - Circuit bank 2 / Sensor 1
P0174 - System too lean - Bank 2
P0155 - Oxygen Sensor - Heater bank 2 / Sensor 1

Gas cap? MAF? vacuum leak?

Just had the Crank Position Sensor replaced at the dealer due to some stalling and blinking M and S lights on dash. Seemed to solve the issue but the SES light came on shortly after.

Truck has 180K. Well maintained. I did the head gaskets and installed new plugs and wires about 30k ago.

Thoughts?

 

At 100k, it's past time for all 4 O2s. You should really do them all at the same time anyway. With a bad maf you usually get some drive train codes like transmission gear ratio incorrect or something. I cant remember exactly. Of course, at 180, it might not be a bad idea to do the MAF too. With that many miles, a lot of sensors are starting to wear out. Start with the O2s and put a little oil around your gas cap seal in case it's becoming unsealed, see where that gets you.

 

Thanks for the prompt response.

 

I would clear the codes and see if they come back before replacing all 4 o2 sensors

 

Already did that in hope that they would go away... They didn't.

 

amazon has the best price for oem sensors

 

I would also hold off on doing the rear sensors as their only function is to tell if the converter is working, with no impact on vehicle running.

 

Buy a scanner and read the live data yourself, look and see what your O2's are doing. Nothing worse than throwing money down the drain on replacing non faulty parts. A lot of people do though....

Like Lordmorpheus said, your rear O2's function is making sure your catalytic converters are doing there job.

Youtube has some great educational videos on it.

 

Guys,

Thanks for all the prompt responses and advice.

This forum is so much better than LandRoversOnly.com - the roar of the crickets is deafening over there...