Causes for a P0174 Code?

[gavin]

For some funny reason i think the gap in the cone filter adapter could also be a factor in this P0174 code.
What else could it be?

is the adapter between the filter and MAF, or MAF and TB?
If it's between the filter and MAF, then that shouldn't cause any issues, as the MAF will (should) be getting an accurate reading.

If it's between the MAF and TB, then the MAF could be getting a lower air-flow reading.

 

[burtonbrd138]

no the gap is at the contact point between the MAF and the adapter for the cone filter. So right before the MAF sensor.
And i have not gone back to the stock air filter and i cant because it is at the shop. But i can make a new adapter that will fit better if that is the problem.

 

[gavin]

I don't think that would cause any issues, then. Granted, it's not good for it to be like that (depending on how big the gap is), but as long as the MAF is reading the air flow through the gap, it really shouldn't cause any codes.

 

[burtonbrd138]

ya that is what i was thinking and a P0174 code is being read from the 02's...right?

 

[burtonbrd138]

I got an update from my mechanic. He said that there is indeed a leak in the intake manifold(didnt say upper or lower) but he said that he put sealant on it because they are made of plastic and sometimes dont sit right. So he is keeping it over night to harden and see if that did the trick.

 

[gavin]

ya that is what i was thinking and a P0174 code is being read from the 02's...right?

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.

Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.

so it means that, yes, the code is being generated by an O2 sensor.

Causes:
A code P0174 may mean that one or more of the following has happened:

The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor.

so yeah... it means that air is being sucked in to the engine, that the MAF isn't reading. So a leak in the intake manifold gasket is definately a likely cause.

 

[burtonbrd138]

i will see what the mechanic says tomorrow. It really sucks walking to school in this really rainy wheather too.

 

[burtonbrd138]

ok so i am getting it back today and this is what the mechanic said. "It appears that the intake you put on may have sucked something into one of the cylinders and for us to fix it may be well over 2000 dollars" I think that is a load of bull **** because the cone filter is well.. a FILTER!!! I think this may be another "blame the mod" cases where the mechanic just cant figure out the problem.

 

[gavin]

what about this gap you said something about?
how big is this "gap"?

if it's large enough for debris to get sucked into the engine, then yes, it's possible debris got sucked into the engine, which could possibly cause horrendous damage.

 

[burtonbrd138]

ok i looked at the intake adapter and there is NO GAP!? I thought there was one but i guess that is just my bad memory but there is where the story gets good!
After getting *****ed at my dad for half an hour for putting an intake in he tells me that the mechanic said that cylinder four is the one with the debris in it.... then i remenber when i bought the truck that it had a constant missfiring cylinder which happens to be four! I replaced the spark plug and it ran good for a while. Then i put on the intake and the debris just so happens to get itself lodged in cylinder four making it rough idle. It all makes sense and it is not the intakes fault in the first place and my dad stopped *****ing at me after that point BUT THE BEST PART is the mechanic that worked on the truck is also the one who sold me a truck with a F#CKED UP cylinder 4 GO FIGURE!!!!!

 

[burtonbrd138]

ok i did some pioneering on the forum. When my CEL was on it blinked, this means that there is a misfire. So i guess my next option is to get new plug wires because the plugs are new and so is the distributer. The main problem is in cylinder four so this may fix my problem. Anything else i should look into replacing?

 

[burtonbrd138]

bumpity-bump

 

[gavin]

isn't the engine a distributor-less style?

plugs and plug wire is a start.
if that doesn't work, swap the coils around. Unless it only has 1 coil? I'm not knowledgable on the 4.0's.

 

[burtonbrd138]

ya sorry the coil pack is what i meant. I will get the codes read again and buy a set of plug wires. What brand is the best and would a higher octane gas help?

 

[gavin]

I'm running a set I bought from CarQuest.
some people swear to Tailor's, FMS, etc. I dunno whether or not they would really make a difference.

and no, a higher octane would not help, especially since it's only a single cylinder that's mis-firing.

If it was a random mis-fire, then maybe

may try running some fuel injector cleaner through too, if you haven't done that in a while. There is always the very slight chance that the cylinder 4 injector is slightly plugged or something?

I'd go buy a can of SeaFoam and dump it in the tank when you fill up next.

 

[burtonbrd138]

ya the mechanic looked at the injectors and said they were fine, i have seafoam at my house and will. But for the hell of it I will get a higher octane. But i am buying the wires and one plug for cylinder four tomorrow. I replaced the plugs about two mounths ago so there is a chance that the cylinder four could be a bad one.

 

[Zenonb]

Hi, I went through this with my 2000 XLT with a SOHC about two weeks ago. The problem was the lower intake gasket. When I took it apart, the upper intake gaskets looked perfect. The lower gaskets were flush with the manifold surface. I heard two theories about this. The first is shrinkage, the second is abrasion due to differenced in COE of eh metal heads and plastic intake manifold. I do not know if either of the two theories is correct. When I saw my lower gaskets, it just jumped out at me as being wrong. I did not see your mileage, but my XLT has 186,470 miles in it.


I would have expected you to get the P0171 code also. If you search the threads for P0171 and PO174, someone has posted a troubleshooting tree, and a how to with pictures. The gasket set cast me $27 at Kragen. It is a two-hour job, but I stretched it into a six-hour job while watching football and going to the auto parts store to adlib the PCV tubing. The aftermarket PCV was not a direct replacement for the OEM PCV.

Good Luck, let us know how you made out.

Take care, ZB

 

[burtonbrd138]

ya t thought it was the lower intake gaskets and i am almost sure that that is what he replaced being around $27. I am almost positive that it is a really bad misfire because it was misfiring earlyer in the year and i replaced the plug which made it a little better so my next thing to replace is the wires and the coil pack is new so i am doing that tomorrow. I will tell you how it goes.

 

[burtonbrd138]

ok i had someone else look at my truck today and they brought forth to my attention an engine knock. I always noticed it being there but i thought is was my leaking cats because of the click but he told me it is most likely a floating valve. I did notice that the gas sticks a little when i have to book it onto the highway, when i let off the gas it keeps accelerating a little. Looks like i have to drive it the way it is..... life sucks:thumbdwn:

 

[jangel]

I would have expected you to get the P0171 code also. If you search the threads for P0171 and PO174, someone has posted a troubleshooting tree, and a how to with pictures. The gasket set cast me $27 at Kragen. It is a two-hour job, but I stretched it into a six-hour job while watching football and going to the auto parts store to adlib the PCV tubing. The aftermarket PCV was not a direct replacement for the OEM PCV.

Good Luck, let us know how you made out.

Take care, ZB

I have these same 2 codes and have searched and searched and cannot find the troubleshooting tree you refer to. In fact, if you search all the forums for p0170 I get 0 results. Maybe the search function isn't working? Maybe is is just me.

If someone knows where I can find the troubleshooting tree, I'd appreciate the help. I'm going to tackle this issue this weekend and will have very limited time, so I'd love to have as much info as possible ahead of time.
Thanks,
John