Code P1130, P1131, P0171 fix

[bluebird]

I have a 1999 Explorer with the codes P1130, P1131, and P0171.

I replaced the upper and lower intake manifold gaskets about 4 years ago that fixed a cold start rough idle issue. After that the car ran perfect.

Recently the engine light came on and the codes above came up. The car idles ok, but periodically is rough. When driving at highway speeds, it will lag once in a while. I noticed the rotten egg smell two days ago, but haven't smelled it since. It does seem my gas mileage has dropped.

I cleaned the MAF sensor, which didn't change anything. I checked under the engine cover and didn't notice any kinks in the hoses. They seem to be sealed.

I am thinking of changing the Oxygen Sensor. It is around $50-$60. If I do change it, do I change the Bank 1 Sensor 2, which is on the drivers side, in front of the cataytic converter?

 

[2000StreetRod]

Bank 1 = passenger side

P0171 System too Lean (Bank 1)
P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1
P1132 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Rich - Bank No. 1

Bank 1 is the bank that has cylinder 1 which would be the right (passenger in USA) side. If you change a sensor I suggest the one on the right side upstream of the cat. Before changing you might check to see if it is caked with mud preventing it from access to the atmospheric O2 level. You also might try adding a bottle of Techron fuel injector cleaner to the fuel tank in case one or more injectors are clogged.

 

[Explodr94]

The O2 sensor could definitely be bad. Before just parts changing check your fuel pressure and listen to your fuel injectors. A bad regulator or injector could also throw those codes.