P0171 and P0174

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2002 Ford Ranger 3.0L 74K(original miles)

Went outside to crank the truck so it could warm up while finishing getting ready for work and instantly got a CEL. Plugged in my code reader and got P0171 and P0174 confirmed for Bank 1 and Bank 2 fuel system too lean. I would love to tackle this myself, but My wife and I both are working seven days a week right now so its gonna have to go in the shop first thing in the morning.

Everything on this truck that could be an issue to these codes is still factory stock parts that it came with from the factory. I have noticed that in the last couple months my daily commute to work has started using almost a quarter tank of gas each way(54 miles each way). So basically 100 miles is costing me half a tank of gas each day nearly. Im preparing for the worst financially of it being a leaking gasket or fuel injectors because it does have a slight but noticeable rough idle and only at idle. Other than that it drives fine.

What else can you think of to look at/for?

Thanks guys.
 
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Did you recently add a fuel injector or combustion chamber cleaner on your last fillup of gas?...maybe even overdose it a bit too much?
Depending on your answer is what I will ask/add next.
 
Well, I was thinking that if you just filled the tank and added the SeaFoam(cleaner) that the CEL would emit due to reading different values in the fuel. But since it was done ~4K miles ago, I am ruling out the fuel system cleaner(FSC). I think that your air/fuel(A/F) ratio sensors in Bank 1 & Bank 2 are now on their way out as this is what has always happened to my vehicles. Why both together? IDK!

I could be wrong but, it's a hunch.
 
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Lean On both banks? I would want to know what the fuel pressure is. In case the fuel pump is getting weak.

Edit; perhaps fuel filter should be replaced as well.
 
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Originally Posted by spasm3
Lean On both banks? I would want to know what the fuel pressure is. In case the fuel pump is getting weak.

Edit; perhaps fuel filter should be replaced as well.


I replaced the fuel filter about 6 months ago.
 
Originally Posted by Char Baby
Well, I was thinking that if you just filled the tank and added the SeaFoam(cleaner) that the CEL would emit due to reading different values in the fuel. But since it was done ~4K miles ago, I am ruling out the fuel system cleaner(FSC). I think that your air/fuel(A/F) ratio sensors in Bank 1 & Bank 2 are now on their way out as this is what has always happened to my vehicles. Why both together? IDK!

I could be wrong but, it's a hunch.


Well those are the original O2 sensors from 2002 so....that is a possibility.
 
Definitely a vaccum leak or failed PCV. Check fuel pressure, smoke test intake system, check volume readings of mass air meter. Probably something simple.
 
Originally Posted by Audios
Definitely a vaccum leak or failed PCV. Check fuel pressure, smoke test intake system, check volume readings of mass air meter. Probably something simple.


That's about where I am at with it. Normally it's the simple crap that is the most aggravating.
 
If it is a 4.0SOHC likely vac leak, replace intake gaskets. I think Ford had a kit. Also clean your MAF sensor. That is 99% of the reason for BOTH codes. The chance of bad 02 sensors with both of those codes is 1%.
 
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Lean on both banks is either too much unmetered air (leak) or to little fuel (weak pump or dirty fuel filter)

Did they come back after you cleared them?
 
Originally Posted by thastinger
Lean on both banks is either too much unmetered air (leak) or to little fuel (weak pump or dirty fuel filter)

Did they come back after you cleared them?


I did not clear them. I am at work right now.
 
Air hose leaks after the maf sensor is something to check. The large rubber pipes get cracks. I spent money and days finding this to be the problem and so easily fixed. Replaced the rubber tubes which had cracks at the bottom where can't be seen, and ran like a new car again and codes cleared.
 
Do, do the normal things like cleaning the MAF sensor and checking the fuel rail pressure, but my bet is on a leaking intake manifold gasket, which is not expensive or too difficult to DIY fix in an afternoon. As far as expense it seems like it's more expensive to keep driving it with such poor fuel economy.

I'd still check all the vac hoses and fittings before diving into doing the intake gasket.
 
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Definitely check fuel pressure.

Does this use a vacuum referenced fuel pressure regulator?

If the vacuum line going to the fuel pressure regulator severs, your fuel pressure will be way too high.
 
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