P1126 and low rpm hesitation - all troubleshooting listed- Help greatly appreciated!

[porschefan76]

Originally Posted by ike84

Hey fan, glad to hear you're making progress. I could be wrong but I think that p1126 is a lean condition? Your negative fuel trim would support that. If you've got new injectors and good pressure then I would suspect a small leak. I know you said you smoked it but as we all know small leaks can be a pita for even the best to find.

Somebody else chime in on this, I don't wanna steer you wrong.

Sent from my POCOPHONE F1 using Tapatalk

Hey Ike! Thanks for following up! Yes, I've had some progress, and it's driving much better, thankfully. I finally experienced those "smiles per gallon" again yesterday. I did notice a SLIGHT hesitation coming back on the gas in third gear yesterday while being slightly aggressive on an empty stretch and corner, but otherwise much improved.

I am honestly not sure one way or the other if it a lean or rich code. I have this excerpt from the Porsche/Bosch DME code list:

In above, being "below limit" can go one of two ways in my mind. If it's referring to the fuel trim being below limit, that would indicate a rich condition to me, because fuel trim would be subtracting from the injector time. If it's an O2 sensor that is below limit, to me that means lean because below .45mV is lean and above .45 mV is rich, unless I've got that reversed. The fact that Banks 1&2 RKAT are negative seems to support rich at idle to me as well, as RKAT is "range 1" so far as I can tell, which includes idle.

Other news and updates, I just had some warm temps in the garage, so I vacuum tested the power brake booster line and it held vacuum. I also started the car, pulled the vacuum hose from the fuel pressure regulator (rpms surged) and pulled about 10 psi of vacuum (over Porsche specification, I wonder if this means anything?). So the intake vacuum appears intact, if not high. That said, once outdoor temps are above 55F, I'll be smoking the intake again to look for leaks.

Anyway, if anything jumps out at anyone, please let me know. I need some next troubleshooting steps.