Help needed with P0171 & P0174 running lean at idle. My fault!

[89Suburban]

I'm wondering if he could have possibly knocked this plug loose?

Or this is damaged?

Or this guy?

 

[89Suburban]

 

[Foggy]

It would have been almost impossible to knock the VLOM plug loose -its your first
picture, although that WOULD cause a check engine light.
The other two are a good possibility - the one at the rear of the intake to
your brake booster is a big one- you'll have to remove the intake manifold to
"really" check it.
I'd try to actually run my hand along both of those tubes in PIC 1 & 2 while the
engine is running to see if you "feel" any air.

Long term fuel trims take some time once they are reset to get to their actual values.
Short terms bounce like a trampoline. And won't cause a CEL unless +or - 25* for
an extended amount of driving.

Make sure you didn't unplug the vacuum sensor that's along the brake booster hose ?????
Otherwise I think you might have to remove the intake to find the issue, which is what
you didn't want to do to begin with.
FWIW, whenever I do these Oil Pressure Sending Units I always do it by taking
off the intake manifold. It's a great excuse to clean all that shit out of there, get some new
gaskets in, and check the VLOM bolts as they loosen up commonly

 

[Kapitein]

It would have been almost impossible to knock the VLOM plug loose -its your first
picture, although that WOULD cause a check engine light.
The other two are a good possibility - the one at the rear of the intake to
your brake booster is a big one- you'll have to remove the intake manifold to
"really" check it.
I'd try to actually run my hand along both of those tubes in PIC 1 & 2 while the
engine is running to see if you "feel" any air.

Long term fuel trims take some time once they are reset to get to their actual values.
Short terms bounce like a trampoline. And won't cause a CEL unless +or - 25* for
an extended amount of driving.

Make sure you didn't unplug the vacuum sensor that's along the brake booster hose ?????
Otherwise I think you might have to remove the intake to find the issue, which is what
you didn't want to do to begin with.
FWIW, whenever I do these Oil Pressure Sending Units I always do it by taking
off the intake manifold. It's a great excuse to clean all that shit out of there, get some new
gaskets in, and check the VLOM bolts as they loosen up commonly

Yes, to be honest I think the inlet manifold is going to have to come off. What a PITA.
Ive been looking on Rockauto and I see for the inlet manifold gaskets there is a '1st design' and a '2nd design' option.

Does anyone know what I will need?

Its an 07 6.2 non afm/dod.

My last course of action today is to play with all the lines again, but im certain (apart from perhaps the brake booster line) that there are no leaks...

 

[Kapitein]

I'm wondering if he could have possibly knocked this plug loose?


View attachment 385989





Or this is damaged?




View attachment 385990





Or this guy?




View attachment 385988

Thanks for the pics and ideas.
Mine is an 07 6.2, so no VLOM. One thing I can rule out at least. The other lines I have replaced with new and as far as I can tell are OK.
My strongest doubts lie with the brake booster vacuum line and its connection in the intake manifold. Unfortunately that means the whole intake manifold needs to come off for fault diagnosis.

 

[Kapitein]

Been out and double checked everything again. The only line I can find any 'play' in is the brake booster line, where it connects to the manifold. I can move that back and forth maybe 3/16 inch, but doing so doesnt seem to affect the running of the car.
Ive resigned to fate and booked myself a spot at my local mechanic, the intake removal and replacement is more than I have time for at the moment.
If anyone can advise on exactly which intake gaskets I will need (1st or second design) that would be awesome

Ill update of course when I can.

 

[donjetman]

If your VLOM is flat/smooth it is the 2nd design.

The first design, built prior to April 1, 2006 contained AFM components, but were left disconnected from the ECM.
The second design eliminated the AFM components altogether.

 

[Kapitein]

If your VLOM is flat/smooth it is the 2nd design.

The first design, built prior to April 1, 2006 contained AFM components, but were left disconnected from the ECM.
The second design eliminated the AFM components altogether.

Thanks. I have a flat valley.

2nd design it is

 

[Kapitein]

I'm going to order up the FelPro MS97126 set.

 

[89Suburban]

Been out and double checked everything again. The only line I can find any 'play' in is the brake booster line, where it connects to the manifold. I can move that back and forth maybe 3/16 inch, but doing so doesnt seem to affect the running of the car.
Ive resigned to fate and booked myself a spot at my local mechanic, the intake removal and replacement is more than I have time for at the moment.
If anyone can advise on exactly which intake gaskets I will need (1st or second design) that would be awesome

Ill update of course when I can.

That sucks man sorry.

 

[Foggy]

The intake removal job is pretty easy. There is no coolant in it..
That's why I don't really understand the importance of doing the oil pressure sensor
job without pulling the intake as it's really easy.. Just my opinion...
The fitting on the back of intake to the brake booster is a swivel type fitting.
It will rotate but you should not be able to move it back and forth.. So you
may have found your issue.

 

[Kapitein]

Fixed!

Intake manifold removed today, found this sealed plastic nipple (somebody here will know the name) broken off close to the fuel rail.... Guess I caught it or leaned on it when replacing the pressure sensor and busted it.

Capped it off and it's running normal again. Fuel trims back to how they should be.

Relieved!

 

[pbr333]

vcume leaks, use wter with it runningto find.squirt botle
also chek tps.

 

[TorqueInd]

I am having the same issue with my 2015 6.2. Glad you found the issue. This post was very helpful. I will be searching for the vacuum leak today. I hope I find it!

Cheers