2002 Ford Ranger 2.3L P0171 CODE HELP!!!

[cory0789]

My truck has not been running in over 6 months due to just no needing it. I cranked it up trying to get it ready to go ahead and sell it and this code came up and it idles rough. It will drive but as soon as I get to a stop sign it goes to a low idle and sometime dies completely and I have to start it back up. I have looked for vaccum leaks and have not found anything yet. I have checked the MAF and it looks good.

My main question is what would cause this if it has not ran in a while? Could the intake manifold runner control on a 4cylinde be it? This is something I had to replace previously but not sure if it can send enough air to cause the P0171 code.

Please help me with any advice on this as it was running perfectly before it sat for this period of time!!

 

[RonD]

Welcome to TRS

P0171 = Lean on Bank 1

Which on a 4cyl means whole engine since it only has one Bank

In OBD2 lingo Lean means the computer is having to open the fuel injectors longer than it has calculated to get O2 sensor voltage to average status, i.e. correct oxygen level in the exhaust

Yes, an air leak is the most common cause for this code.
Computer is getting incorrect air flow data from MAF sensor because not ALL the air coming in is passing thru the MAF sensor, so computers calculation of fuel needed is low, so it has to open injectors longer to correct the mix.
To set a Lean code the vacuum leak needs to be a fairly good size leak, PCV hoses are often the source, could even be PCV valve is stuck open.


How full was the gas tank when you parked it?
Gas in the tank can(will) evaporate which lowers its energy level(burn rate), if that happens then computer would have to open the injectors longer to balance O2 sensor

You would also get rough idle because of the poor gasoline quality.
If you haven't add more gas then I would do that, and put in some higher octane, 91, to bring up levels in older gas

 

[cory0789]

Thanks,

I will try that as the truck is about 1/2 a tank a fuel. The PCV valve I have looked for and cannot locate as someone else had posted about it when searching for this problem. that will be something I try to find but wanted any other easy fixes before i got down into it.

 

[AzLizard]

Mine turned out to be caused by split hose at the fuel pump.

 

[RonD]

This is a How-To with pictures for 2.3l Duratec PCV valve replacement: https://www.ranger-forums.com/engine-drivetrain-122/how-change-dohc-2-3l-pcv-valve-116900/

It is part of the Breather assembly so whole unit should be pulled off.

I would check the hose FIRST, looks like it runs back towards firewall then up to rear of intake manifold