DTC Too lean

[Wolfgang10]

I drive a 2002 Ford Ranger v6 4.0l.
roughly 93,000 miles bought used two years ago.
Check engine light came on the other night and when I went to autozone they connected their obd ii scanner to it and it came out with a P10something trouble code and said it was too lean.
No power loss or anything noticeable while driving. Still does highway speeds fine and idle is normal.
This makes me want to rule out any vac. leaks or fuel delivery problems. I figured if it was a dirty fuel filter/ fuel pump, id get a bog down or something.
I plan on changing the fuel filter anyway, but want to fix the problem first.

Was able to change 3 spark plugs before work and will have to change the others tomorrow. The electrodes were barely there. Anyone know what causes this?
Plan on running some lucas cleaner throught it next time i get gas to clean injectors a bit.
Anyone had a similar problem?
I searched the forum and saw Rolex had an issue with his 5.0 but didnt think it was similar enough.
Almost bought new tires this week, but will have to wait just a little longer lol

 

[alien13]

I'll tell you that if you can remember the code it will be alot easier to find out what the cause it. "P10something" doesn't help.

 

[Wolfgang10]

My fault. It was either P0171 or P0174. Both indicate too lean of a air/fuel mixture, and one is for bank 1, the other is for bank 2.

 

[hamz9561]

Had a similar problem with my '02 F150. It was the O-Ring seals on the intake manifold that needed to be replaced. The V-6 has a 2 piece manifold that will leak and give that lean code. I found this out after 2 fuel pumps and several fuel filters.

 

[Wolfgang10]

how did you find this leak? I've read that you can spray carb cleaner near the mainfold and if there is a leak, it will suck in the carb cleaner and be very apparent by the way the engine runs after it sucks it in.
I havent tried this yet but will tomorrow if what I work on today doesn't work.
I found a thread on another forum about a small 90 degree elbow. Its known to split and throw the same codes. It is hidden under the coolant hose by the oil fill.

 

[Rolex]

After hundreds of wasted dollars and a lot of stalling out, I found a new shop filled with automotive geniuses.
My problem was the temp sensor which kept telling the computer that the engine was always 5 degrees, causing it to run filthy rich.
On a side thought, if a sensor went bad telling the computer that the engine was hot or at a different altitude, it would adjust the mix to lean. Mass oxygen sensor? Just a thought.

 

[bgbdwlf2500]

After hundreds of wasted dollars and a lot of stalling out, I found a new shop filled with automotive geniuses.
My problem was the temp sensor which kept telling the computer that the engine was always 5 degrees, causing it to run filthy rich.
On a side thought, if a sensor went bad telling the computer that the engine was hot or at a different altitude, it would adjust the mix to lean. Mass oxygen sensor? Just a thought.

That was my first thought, little electrical contact cleaner will clean it right up... leaks are unmetered air which will cause problems, just like a nitro engine the carb cleaner trick is a good idea too, if there is a leak the engine will suck it in and you will get a faster idle

 

[2revo1maxx]

Use an unlit propane torch, it's safer and works better...after changing the fuel filter. I'm guessing you need one if the plugs were that bad. You should do a fuel pressure AND flow test as well, sometimes the pressure is there and the flow is not, something that will definitely cause a lean condition. I'm not ruling out a bad intake and/or plenum gasket, but those problems usually set off different codes.

 

[Wolfgang10]

I feel real dumb after reading my initial post. the electrodes on the spark plugs were barely there.....because they are supposed to be like that lol. They are fine electrodes which are supposed to be better than the regular ones. Eh. I got the regular ones to replace the fine ones.

I checked my pcv elbow and sure enough it was cracked. So i spent 6 hours changing the last three spark plugs and went to get a new elbow. Of course they didnt have mine, so I bought one for a dodge and cut to fit.
Will have the code cleared tomorrow on the way home from school to see if the problem is fixed.

 

[2revo1maxx]

Your original plugs were platinum or iridium. Regular ones should be ok, but they won't last anywhere near as long. Couldn't you access the plugs through the wheelwells?

At least you found a problem that's probably it.

 

[Wolfgang10]

Well I could change the 3 driver side no problem. Took roughly about an hour. The passenger side was the pain. The plug closest to the firewall is actually pointed backwards. I thought about taking out the inner wheel well, but was able to pull back a small flexible material and snake my hand up in there. Getting to it was the easy part. The difficult part was tryin to figure out what combination of extensions and flexible joints would make it possible to screw out. The even harder part was figuring out how to get the "spark plug socket" off of the plug. Because of the rubber ring inside, when I tried to pull it off, the extension came out of the back.

I replaced the cracked elbow and was hoping the computer would reset itself. It didnt. So I took it to an auto store and they told me they wouldnt clear the codes, because its "illegal" thanks to some emissions crap. He thought I was tryin to sneak past an inspection. So I took it to another store and explained to the guy why I needed it cleared. He said he couldnt, but cleared it anyways because I told him I am trying to see if I fixed the problem or not.
So far, the light is still off.

Thanks friends!!!!

 

[MR4X4KING]

when you want to reset the codes just disconnect the negitive battery cable for 2-3 minutes then put it back on

 

[Rolex]

That's correct.

 

[2revo1maxx]

It may take a while before the code comes back....if it does. You have to do drive cycles so all the rediness monitors can turn on again. Unhooking the battery cable doesn't always work, because some vehicles have capacitors in the works, and some codes can re-appear seconds after you fire it up.