Oxygen sensor help
 

I recently took my truck(97' ranger) to a hardware parts store and had a friend there run his diognostic code reader. it came up with this P0171- which means that there is to much air in (bank 1) and i also got P0174(bank 2) which is basically the oposite side with the same problem. I have just did a small amount of searching and some people are saying they clean the MAF sensor. does that work? and when it says bank 1 and 2 what sensor is it talking about. Thanks matt

Cleaning the maf is 5-7 bucks and 10 minutes of time. O2's are nearly 75 a piece for oems. They will take about 15 minutes a side to change IF they are not stuck in.

If your over 100k you need to both. Plugs and wires cant hurt either.

ya it has 130k+some change. the wires do you mean the whole thing or just to the plug part

new spark plug wires and spark plugs

Bank 1 = passenger side
Bank 2 = driver side

The two O2 sensors that are being read for these codes are the ones closest to the engine on each of the two banks.

Here are a few general possibilties for lean codes P0171/P0174. I'd rank them like this with most likely at the top of the list and least likely at the bottom:

• Vacuum leak
• Leak between MAF sensor and throttle body
• Dirty MAF sensor
• Dirty injectors
• Low fuel pressure.
• Bad oxygen sensors

These codes are not caused by an ignition problem. At high miles, it may well be time to replace the plugs/wires but that is a separate issue.

BTW, please remember to include the year/model/engine/transmission/mods/etc. when asking any technical questions. Sometimes there are known problems that are specific to a particular combination.

Oops?!? 1997 ranger 4.0 5 speed 4x4. thanks for the help

how do you check to see if there is a vacuum leak and between MAF and throttle body?

Easiest way i know is to spray the hoses with brake clean if the engine starts to die the you have a vacum leak where your spraying.

Also, you can view the fuel trims under loaded/nonloaded areas of the map to view where your system is dumping extra fuel to compensate for the lean-ness that the hegos are measuring. Vacuum leaks are prevalent under low load due to the fact that the throttle plate is a vacuum leak itself, when you open the throttle it hides the effect of small vacuum leaks. I have a great post on these codes but the mods never stickied it (you should search)