ok guys ive been getting this code over and over no matter what I do...... heres what ive done in order....
1. pulled the o2 sensors off and attempted to clean them.
2. pulled the egr valve off and cleaned it and then took the intake plenum and cleaned where the egr holes were clogged.
3. replaced the PCV valve and tried to check for vacuum leaks.
4. cleaned the mass air flow electrical plugs( the mass air flow is still considerably new)
5. replaced all 4 o2 sensors

I went for a drive today and i still got the code!!!!! is there ne thing else that you guys can think of that might possibly be the reason????
thanks!

 

fuel filter? Those are lean codes. Also check all the rubber elbows in the pcv. Also injector flush. BG products are very good.

 

ahhhhh...... ill check the fuel filter! i already checked those elbows that you were talking about. and ill do a injector clean and ill let you know

 

I bet ur fuel filter is so clogged that when you take it off there is going to be all this fuel back pressure coming from the injectors/fuel rail

 

For future reference - lean codes both banks are NEVER caused by defective O2 sensors, and it's a waste of money replacing them - *especially* the rear sensors, the ONLY thing they do is report on catalyst efficiency. The codes are almost always caused by a rotten or cracked PCV elbow behind the intake manifold.

 

see thats what everyone says but the PCV elbow behind the intake manifold isnt an elbow and plus I went on a hunt to find a new one to replace it because its starting to rot and look old but i couildnt find it from any store.... do you have any ideas in where I can find that piece? thanks!

 

Have you been to the dealer yet? I believe they have the entire assembly from PCV to manifold for about 35 bucks.

 

see man... thats the thing everything else is fine execept that rubber adapter that connects to the intake plenum... i dont wana have to buy the whole entire piece if I only need that one little specific part... ill basically be paying 35 bucks a rubber adapter lol

 

I had those codes...ended up being a worn out IAC valve...replaced it, cleared codes, and hasnt returned yet...good luck

 

Replace the whole thing, geeezzz. If your that cheap, match up your weathered piece @ O'Riely's/Murray's. They have a big section with quite a few of those little rubber hose sections. You must have this set up -





These develop pin holes, hard to see. IF your using a Fram PCV valve, these restrict flow so much, pin holes may enlarge when she's running,- it's killing your engine, she can't breath, but she's trying her best. What Fram replacement parts do best - Destroy..Just so you know.

 

ok i replaced the fuel filter and the code tripped the next day...... took the other advice and went today and got a brand new IAC valve..... went for a ride and it hasnt tripped a code yet..... it usually doesnt until i go to make that long drive over to the school.... ill let yall know tommorow if indeed the IAC valve was indeed the problem..... If it throws the code again then it could be only one other thing... the PCV valve boot at the intake plenum... ne ways ill let yall know

 

well..... took her to work and guess what........... THREW THE ****** CODE! ugh......... well i guess ill call the ford dealer tommorow and get that boot on order..... if it throws a code after that im out of options and ill have to take it to a professional......

 

F150 Professionals are here. But no, we can't preform the actual work for you from here, - just give you direction..

When both banks test positive for lean, -the MAF is excluded, if intake air tubes are intact and IAT grommet is good, you head right to the PCV system, then rule out fuel. The problem is usually found at the PCV assembly.

Lean issues are common and fairly quick/simple to figure out.

 

How many miles on the truck? It's most likely a vacuum leak but it could be something else. Missfires can cause lean codes too. So could an exhaust leak before the O2 sensor. But I doubt that's whats happening.

When reading codes you have to pay attention to the specific language used with the 0171 and 0174 codes. That's pretty vague and not a good translation of the code.

I will translate this computer language into proper english. This should give you some clues....
1- the computer is able to compensate and the engine IS running at stoich. So, that eliminates any major problem with fuel delivery or sensor equipment. Since you don't have any "lack of O2 switching" codes, then you know it's holding stoich.

2- In a nutshell, the ammount of air coming into the engine isn't jiving with the ammount of fuel it is requiring.

So... my advice is to

1- find the vacuum leak
2- clean the MAF sensor

Unplug the battery for 5 minutes then reconnect it. Test it out for a day or two. Report back and let us know how it went.

 

chester said stoich.

Uknow, most are going think that's a typo.

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