wassup everyone. need some insight. my ses light went on 2 day, got it scanned and code 172 popped up. .it states its the o2 sensor, left bank running too rich... couple of hours later ses light turned off. now... do i still change the o2 sensor? im assuming i do. also, is there anything i can do so that the car wont have 2 throw me that same code. thanx. peace.

 

The code is set by "fuel trim system running too rich". Generally means the long term fuel corrections have bottomed out at 108, and the O2 sensors still feel its running rich, in spite of pulling all that fuel. Could be caused by a faulty O2 sensor, wire, ground, or by things that cause a "rich" condition - EGR valve leaks, injectors dripping, fuel pressure too high, leak in FPR diaphragm, saturated EEC canister, etc.

Swap the O2 sensors from left to right. If the problem follows the sensor, its a sensor problem. If the problem stays on Bank 1, its something else.

 

thanx injuneer. i just bought a new o2 sensor. im gonna have my cousin whos a mechanic check 4 the other possibilities. the code it spit out was 172, is there anything i can do or check if its any of the other problems you have mentioned. i do notice that ive been eating alot of gas recently with a little surge when the gas pedal is first pressed hard.