1997 Ford Explorer • 6 cylinder FWD Automatic • 165,000 miles

I have a 97 ford explorer and it threw the code p1131. It idles really rough at times and sometimes even kills. I can also smells unburned fuel coming out of the exhaust sometimes too. I was just wondering if you had any ideas on what it could be
January 19, 2011.

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

Any of these could be the cause of the code.

Electrical: * Short to VPWR in the harness or HO2S
* Water in the harness connector
* Open/shorted HO2S circuit
* Corrosion or poor mating terminals and wiring
* Damaged HO2S
* Damaged PCM

Fuel System: * Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system

Induction System: * Air leaks after the MAF
* Vacuum Leaks

PCV system: * Improperly seated engine oil dipstick

EGR System: * Leaking gasket
* Stuck EGR valve
* Leaking diaphragm or EVR

Base Engine: * Oil overfill
* Cam Timing
* Cylinder compression
* Exhaust leaks before or near the HO2S(s)
Start by checking all the parts you can visually check. More than likely it is an exhaust leak before or near the HO2S(s)