My ranger shows code P1131 but reader says not found. Does anyone know what it means and what i need to do to fix it? Thanks

 

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

try replacing the sensor first theyre pretty cheap...how many miles are on your truck...and a little more info about your truck would help

 

1998 4cyl 5speed 2wd 165000 miles. It had a slight miss every now and then. Thought it might need a tune up. Today the check engine light came on and it just bogged down and wouldn't even pull itself. Finally came out of it and starting running better and thats the code it showed. How hard is it to change O2 sensor?

 

not hard at all...this is the upstream sensor and that is in front of the cat.converter

 

Thanks for the info. When i get it changed i'll post and let you know if it solved the problem.