Hi,

I finally got around to checking the codes with my obdii scanner and it reported the following:

P0456 - Eval leak monitor small (0.020) leak detected
P0131 - 1/1 o2 sens short to ground
P1195 - 1/1 o2 sensor slow during catalyst monitor
P0000 - wtf

Since I just recently bought the truck, I cleared them to see what would come back. After about 30 min of driving, I received a

P0171 - 1/1 fuel sys lean

It's a 02 Dakota 3.9L with the California emissions junk. Generally runs ok, although it seems like it could run smoother. I've replaced the plugs (have the distributor rotor and cap, but not installed yet.) and am getting about 13 mpg which seems a little low.

What I've researched seems to indicate I need to replace the drivers side upstream o2 sensor. Does this seem valid or are there other things I should check first?

If I do replace the o2 sensor, any recommendation on part? At rock auto, the one I found is an NTK # 23137.

Regards,
Bill

 

Replace both O2 sensors - get the cheapest one you can find they are not rocket science & the cheap ones work as well as the expensive ones. I dont know the part number.

Also replace the gas cap. Thats the cause of your p0456.

The P0171 should be fixed by the O2 sensor.

Not sure what to tell you on the p0000

 

Thanks for the feedback. Since it's the California emissions, are you really saying I should replace all four?

Also, thanks for the tip on the gas cap.

 

Just replace the upstream one(s), before the cat. I know California has strict emission laws but the downstream one's aren't really important.