2008 Escalade P0455, P0172 & P0175, pulling my hair out.

[Doubeleive]

See what the temps and maf readings are via what the computer is reading, a temp gun serves no purpose on this unless you are verifying a good/bad sensor
particularity when it is in the hard start status.
it's just a guess, it could be a variety of things

 

[93M6Formula]

See what the temps and maf readings are via what the computer is reading, a temp gun serves no purpose on this unless you are verifying a good/bad sensor
particularity when it is in the hard start status.
it's just a guess, it could be a variety of things

What I meant is I measured the temp of the converters, not the sensors. All sensors read what they should.

 

[93M6Formula]

Here's an example of it idling last night in closed loop.

 

[93M6Formula]

Here's the MAF reading.
I did another crank relearn and also reset fuel trims which didn't help.

If I jump on it while rolling you can feel it surge in and out of power.

 

[Fless]

Nothing wrong with STFTs within 5% either way, those are great. I was going to suggest resetting the LTFTs with your scanner but you said you did that. After that, are the ST and LT fuel trims now both within 5% at idle? How about at 1500 rpm or so, what do the STFTs do? (assuming closed loop)

 

[Doubeleive]

I am probably not the right person to "advise" here but...
it's apparently running lean so too much air or not enough fuel
have you checked for a vacuum leak? spray around the intake and listen for any change in idle also be sure the intake housing is on correctly and nothing is loose (double check)
if that does not reveal anything then maybe start pulling one injector at a timer and check spray pattern
I could be way off base, so don't take my word for gospel, just throwing idea's out there.
@iamdub any idea's?

 

[Fless]

I am probably not the right person to "advise" here but...
it's apparently running lean so too much air or not enough fuel
have you checked for a vacuum leak? spray around the intake and listen for any change in idle also be sure the intake housing is on correctly and nothing is loose (double check)
if that does not reveal anything then maybe start pulling one injector at a timer and check spray pattern
I could be way off base, so don't take my word for gospel, just throwing idea's out there.
@iamdub any idea's?

It's the opposite -- the codes showed that the PCM was taking away fuel (negative trims) because the O2 sensors were saying it's too rich. With the LTFTs reset to zero, and the STFTs within 5%, there shouldn't be any rich codes. That is, unless the STFTs start going way negative again.

EDIT: so what is the remaining issue, hard starting?

 

[iamdub]

If I jump on it while rolling you can feel it surge in and out of power.

This pretty much pinpoints it to a faulty sensor or actuator or the circuit connecting it. Do you have a way to monitor the VVT cam phaser (probably CMP), MAF, MAP, TAC and TPS to compare them all?

 

[petethepug]

Is it running the original carbon canister full of those wonderful carbon pellets?

 

[swathdiver]

With LTFTs like that I'd say you have a massive vacuum leak. Check the intake and intake gaskets. Get a spray bottle and watch the trims or O2 sensor graph as you spray water around the intake connections and gaskets.