I'm showing a P1311 code on my truck which indicates it's running lean. Anyone have any suggestions on what the culprit might be?

 

A 1311 code is not a normal code for a 4.6/5.4 gas motor.
Re-read the code or clear it to see what comes back and/or try another reader or scanner.
It won't hurt to get rid of old history and see what you get the next time.
Good luck.

 

I have a 96 ranger that gave me that code. I am getting this same code. My truck just doesn't have any power. Sometimes though it runs fine and just out of the blue it starts losing power and falling on its face. I have changed several parts and still can not find the solution. Also when I am filling up with gas, the gas keeps kicking off like the fuel is coming back up the neck. Someone please help me.
Here are the parts I have changed already.
Fuel pump
Fuel filter
Fuel relay
Idle Air Control
Mass Air Flow
Both Oxygen Sensors
Muffler
plugs
plug wires
I think thats everything. Any input would be greatly appreciated. It's kinda funny cause somedays it runs great and others I can barely pull out and can't pull out on hills because it just doesn't have the power.

Very Confused,
James

 

Gas fill nozzles will release on these trucks fills if the auto nozzle detects to much fuel in the filler neck. It's normal.
Some filling station nozzles are set too sensitive.
Many trucks now have a syphon preventer down the neck so gas cannot be stolen. These can impede fast filling as well.
Fill at a slower rate and hold the nozzle pointed straight down the filler tube.
.
The 1311 is not a lean running code.
It is associated with an ignition monitor function that may or may not be implimented on some models and years.
Some readers store definitions of codes for general use and are not correct in some instances or are mis interpeted.
There are nearly 2000 codes in the program so some may come up falsely now and then when the program can't determine the correct decision.
Dosen't happen very often but it can.
Yours is either a 4 cylinder or a version of the small v6 engine.
Instead of throwing parts and money, it's wise to use a good scanner and trap the fault when it happens so you may get a lead on the intermittant issue and have some idea what hardware should be looked at.
This is why diagnostics and live running data is available from the computer using a Scanner.
A dealer tech would have to look at it this way but even they guess at times then it results in a return service call and an unhappy customer.
Sorry it's not simpler but this is the way it is.
Good luck.

 

I might have typed the code wrong. Its either 1131 or 1311. I looked it up and it said it was manufacturer control: Fuel Air Metering. I have had it put on at least 4 different cpu's. They all said the same. To me it sounds and feels as if the exhaust is building up somewhere and just choking it too death. When it is running good, nothing out of the ordinary happens when it starts to run bad. Sometimes when i start in morning it just starts out bad and stays that way for a couple weeks. then it'll start running great for a week. As far as the gas overflowing, it happens on the same pump. Sometimes it will fill up without kicking off. Other times it kicks off every 30 cents. Is their some type of breather hose that could be clogged and not working. IDk. I forgot this in the first post. But i am almost positive the truck has been flooded. I didn't know this when i bought it.

 

I do like where you say "trap the fault". I have tried to pay attention if I do anything different when it changes or if the truck does. I think the hot temps outside and Cheap gas make it run worse. It seems to like Marathon gas the best. But sometimes still runs like crap on it.
And when i say run bad. I mean that it barely has the power to pull out in 1st. It will not pull out on a hill. It backfires when u let off gas. I have to run 2nd gear to 45mph to keep from falling on my face when i hit 3rd. When idling it constantly revs up and then idles down. When it does this while i am driving my brakes don't work when it idles up. But work fine when its idling down or just idling. The other morning I added brake fluid and the idle stayed high while I was pouring and lowered when I quit and put on lid. Very weird. Normally i would push a problem like this over a hill but it has became a challenge for my dad, brother, and myself. Any help would be appreciated.
My email is kybigbluefan@live.com if you would like to send an idea to me there. Thank you.

 

I see you got over into the right forum with your problem.
You have to get the correct code to avoid waisting time and money working on other parts that are not involved.
This is just a guess as a result of not knowing what the code is for sure but the actions you discribe seem to be related to the air intake "after" the mass air meter.
Closely look at all the hoses for cracks of some sort that are flexing open with engine movement and letting a large volume of air enter.
Only thing with your brakes is the vacuum hose. It may have some relation to the problem when you may have moved it while the engine was running and let a lot of air in.
Look for loose throttle body bolts etc.
Any place 'extra' air can enter will raise the idle speed, make the air-fuel ratio too lean, cause the PCM to add fuel and create different reactions while driving. Backfire being one possibility on decelleration.
Trapping a fault would require a mid grade scanner with that ability set up to do a trap while driving providing the fault is not there before beginning the trap attempt.
I can't help you any further so good luck with it.

 

I think under the circumstances, since you now know or think the truck may have been flooded, it's possible that the problem is a short or corroded wire/connection in the fuel pump circuit. Next time it's running bad try to check pump pressure, and likewise when it's running good. A short somewhere may be reducing voltage to the pump, and that seems like a cause for low pressure and volume.

Any unusual rattling in the exhaust ? Might be loose parts inside a Cat. Sitting a certain way internally could partially block exhaust flow, hit a few bumps and move them around, and it runs OK again ?

Dave

 

i agree with this......
my mustang started doing the same thing after i had a friend change the plugs while i put a clutch in. he left the hose clamp on the back side of the maf....
so start there. check all of your intake connections