Ok my check engine light came on and i took a trip down to the local autozone an had them run a diagnostic scan and it came back and said something like the #1 cylinder was too lean or something like that the code was PO171.Anybody had this?if u have pleese help!

 

bank 1 running lean.

 

Basically this means that an oxygen sensor in bank 1 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

A code P0171 may mean that one or more of the following has happened:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
* There could be a vacuum leak downstream of the MAF sensor.


Possible solutions include:

* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure

 

my 4.6 cougar threw that code and it ended up being a bad O2 sensor

 

yea a faulty sensor can throw that code too, happened on my car.

 

Well i had hoped it wasnt an O2 sensor since i replaced all freakin 4 of em about a year ago!Man that cost out the A$$

 

1st do these then if that doesnt work then its prob your 02 sensor.

 

Ok now this other guys tellin me its a fuel injector [:'(]?Idk.Ok also when im i rev it up it idles down almost like its dying but doesnt and also sounds like it has a slight skip in the exhaust.Anybody know????

 

yeah my cougar did EXACTLY that when the 02 sensor crapped the bed. oh and i also found a bad spark plug which is why the 02 sensor died becasue that cylender wasnt burning fuel and it clogged the sensor. check those plugs ill bet its the same exact thing. its really wierd how you say you have those problems cause thats identical to the way i described it to my friends when my 96 cougar did that. its got the same engine. i guess its got the same problems too!

 

O2 sensor isn't the only possibility. A vacuum leak will throw the same code in bank 1, so will a fuel restriction in the right side.