Please help! Code p0171 p0173!

[northernexp]

Hey guys I was hoping you could help me out, my truck has been running rough lately and I got a scanner today and got codes p0171 and p0173, lean banks.
I did some reading online today and I found a few helpful links and acpl YouTube videos showing some common problems and fixes etc.

I tried all the possible solutions that I could find, I pulled the line at the rear of the intake where most people have found that the rubber elbow on the rear of the intake would be cracked, I pulled that whole line today and inspected and cleaned it, I even wrapped it in electrical tape Incase I couldn't see any possible cracks, still no luck. I cleaned the with maf cleaner put in some fuel injector cleaner,, cleaned the throttle body, but Im still throwing the same codes...

Could it be the volant intake? Any help would be really appreciated!! Thank you!!

 

[bedrck46]

did you clean the exhaust ports in the throttle body? could also be the dpfe (EGR Pressure Feedback Sensor) needs replaced Check gas cap, possible fuel pump problem just a few on a list of possible causes

 

[northernexp]

did you clean the exhaust ports in the throttle body? could also be the dpfe (EGR Pressure Feedback Sensor) needs replaced Check gas cap, possible fuel pump problem just a few on a list of possible causes

No I didn't clean the ports in the throttle body, I'll check the egr today as well as the gas cap, thank you very much for the input

 

[bedrck46]

Keep us updated I am sure others will respond with some other suggestions

 

[northernexp]

Thanks I will, I'm going to look around today and see if i can borrow a smoke machine from somewhere, unless somebody has any other suggestions or If anyone knows a backyard method of applying smoke to the intake to check for vacuum leaks? Thanks again much appreciated!

 

[bedrck46]

a good can of carb cleaner sprayed around the vacuum hoses will cause an increase in RPM's

 

[Lightnig]

Once vacuum fittings and hoses start drying out and cracking they will no longer reliably seal, it is not worth the effort and heart ache trying to 'fix' one, just replace it.

The Ford PCV hose/valve assembly is reasonable, includes the PC valve, the hose and elbows, and is almost a guaranteed fix for P0171 and P0174 codes.

See This thread: Rough idle? P0171, P0174? Here's what you need to check first!!!

PO173 is Fuel trim malfunction (bank 2). From my understanding is typically caused by fuel system problems, but bad spark and faulty PCV system can also cause the code to be thrown.

Thanks I will, I'm going to look around today and see if i can borrow a smoke machine from somewhere, unless somebody has any other suggestions or If anyone knows a backyard method of applying smoke to the intake to check for vacuum leaks? Thanks again much appreciated!

a good can of carb cleaner sprayed around the vacuum hoses will cause an increase in RPM's

My ex brother in law was/is a mechanic whom I trusted completely and he swore by a small handheld propane torch. Turn on the gas very low, but do not light, then use the nozzle to follow vacuum hoses. I never had the guts to try this method myself, always felt like I was going to blow up the engine or something else stupid like that, but the B.I.L. swore by it...

 

[northernexp]

Once vacuum fittings and hoses start drying out and cracking they will no longer reliably seal, it is not worth the effort and heart ache trying to 'fix' one, just replace it.

The Ford PCV hose/valve assembly is reasonable, includes the PC valve, the hose and elbows, and is almost a guaranteed fix for P0171 and P0174 codes.

See This thread: Rough idle? P0171, P0174? Here's what you need to check first!!!

PO173 is Fuel trim malfunction (bank 2). From my understanding is typically caused by fuel system problems, but bad spark and faulty PCV system can also cause the code to be thrown.






My ex brother in law was/is a mechanic whom I trusted completely and he swore by a small handheld propane torch. Turn on the gas very low, but do not light, then use the nozzle to follow vacuum hoses. I never had the guts to try this method myself, always felt like I was going to blow up the engine or something else stupid like that, but the B.I.L. swore by it...

Thanks for the tips! I tried that one hose that you referred to a few times actually, I took that whole assembly apart to check it for leaks, and I even taped the elbow fittings on each end with electrical tape as a temp fix to see if that was the leak, but still no luck

 

[northernexp]

So would bad spark plugs cause this as well? I believe they are due on my truck...

 

[bedrck46]

if they are due I would change them and if you don't put new coils in at least put new boots on the plugs You didn't say anything about misfire so plugs and boots wouldn't hurt

 

[jbanks]

Fuel filter fixed this for me. I got a nice increase in power as a bonus. Couldn't get enough fuel to the engine, no matter how much the computer was trying to add!

 

[northernexp]

Fuel filter fixed this for me. I got a nice increase in power as a bonus. Couldn't get enough fuel to the engine, no matter how much the computer was trying to add!

I just changed mine last month.... So I don't think it's that either... Dam this thing is beginning to piss me off lol. Thanks for the suggestion though much appreciated!!

 

[northernexp]

if they are due I would change them and if you don't put new coils in at least put new boots on the plugs You didn't say anything about misfire so plugs and boots wouldn't hurt

I was planning on doing the plugs in the spring, I guess I might be doing them sooner lol... I am thinking back to the first time I noticed it ran rough and I remember happened immediately after washing the engine bay, and I sprayed the engine while it was hot, I know I'm an idiot... Could I have damaged something then? Because I noticed it tab tough for a bit but seemed to go away, bit now that it's cold it's gotten worse, enough to throw codes

 

[jbanks]

I have heard about Leaking Intake Manifold Gasket's many times too. You should be able to find that with the carb cleaner or propane...

I saw some videos(or maybe it was just a description) about DIY smoke machine. That would be worth looking into. Or...maybe you could find a shop with a smoke machine that would figure it out and only charge you a diagnostic.

 

[northernexp]

I have heard about Leaking Intake Manifold Gasket's many times too. You should be able to find that with the carb cleaner or propane...

I saw some videos(or maybe it was just a description) about DIY smoke machine. That would be worth looking into. Or...maybe you could find a shop with a smoke machine that would figure it out and only charge you a diagnostic.

I checked the vacuum line that runs out of the drivers side valve cover to the volant intake and the 2 lil rubber elbows on the line and they were OK as well as the other line that rubs from the volant intake to the idle air control valve and that line was free from cracks as well...

While I was sitting there looking at the intake I noticed that the 2 hoses running from the volant intake to the engine weren't exactly in a straight line in relation to the hoses, and that the plastic tips on the volant intake were pressing more to one side on each hose, enough that I think air might have possibly been entering the system, so I got 4 small hose clamps and clamped the 2 hoses, one at the volant intake and another 4" down the aftermarket hoses where it goes over a and attachés to the factory line.

I also noticed the other snack sensor that goes right after the maf sensor sits in place with a rubber washer type deal, the sensor skies on and the tension caused by the rubber washer is what is doused to seal that sensor but it isn't exactly a tight fit and can come loose easily, so it being airtight is questionable as well.

I sealed it temporarily with electrical tape wrapped around the entire intake tube about 8 times to make sure it's good and sealed, just to diagnose my problems...

I drove for 15 minutes afterwards with no codes and it noticeably running smoother while I had my feet on the brake at lights, they was when it would rub is roughest. I'm going to go for a drive in a bit to see if the codes come back

 

[northernexp]

I went for a drive again after sealing up the 2 hoses that come out of the volant intake and went for a drive, the truck ran nice for a bit threw the p0174 code again, so it's not the 2 hoses that come from the volant intake or where they run to...

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[northernexp]

I think the next thing that has to be done is to get a smoker or make a smoker of some sort to try and find where the leak is coming from because I'm running out of ideas...

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[jbanks]

The other thing I remember. Could be an exhaust leak near the first 02 sensors. But since you are getting both bank1 and bank2, I find this unlikely.

 

[northernexp]

The other thing I remember. Could be an exhaust leak near the first 02 sensors. But since you are getting both bank1 and bank2, I find this unlikely.

Thanks for the suggestion!! I'll take a look at that...

I remember someone saying that it might be the spark plugs... Does anyone know roughly how many hours it takes to do the plugs?

 

[northernexp]

OK so I bit the bullet and started to remove the spark plugs, driver side first. As I was removing stuff to get to the plugs I was unplugging 2 small vacuum lines and I noticed that the 2 lines were cracked pretty good, could this be the reason for my 171 and 174 codes? I took acpl pics. I am going to fix those lines and finish up the spark plug job, I'll report my results after I finish.