P1126 and P1133

[blue62]

Originally Posted by morgal48

Battery is less than a year old - 13.76 V output.
Plugs and coil packs were replaced 23k miles ago. No misfires.
New O2 sensors cause that was all I could come up with after replacing the MAF (about 2500 miles on the new Bremi).
Still on jack stands - I flushed the brakes as well. I'll have it down today to see how it drives MAF-less.
Lastly, the double row IMS was installed 20k mi. ago. Original looks like new. Just wanted that off the table. :-]

Does the ECU reset every time I change the parameters by removing/replacing the MAF? If that is the case, does it "see" the settings from no MAF, then compensate when I start the engine with the MAF installed, going lean to rich, and essentially flooding the engine? Or does it move the opposite way and starve the engine of fuel? Or neither? IIRC the O2 sensors do not affect things until they reach temperature, relying solely on the MAF.

I don't believe the ECU resets when you unplug the MAF sensor.
With the MAF unplugged the ECU simply has no way of knowing how much air is entering the intake.
So The ECU reverts to a set fueling map that works under general= average running conditions.
When you plug the MAF sensor back in now the ECU uses the MAF sensors signal to determine the amount of air entering the intake and adjusts fuel to air accordingly.

When the MAF is working properly it is very precise in measuring air intake.
So it is not going to suddenly go from lean to rich or rich to lean just by plugging the sensor back in.

When you have a bad or faulty MAF sensor and you replace it with a good one the ECU does go through a bit of a relearning curve as it adjusts fuel and probably ignition timing to the now proper air intake readings.

This is why when you replace a faulty MAF with a good one the engine may idle or run a little rough for the first few minutes after replacing the MAF.

From what you described in your first post :
If you have no vacuum leaks which seldom cause an engine to stall as you increase RPM
I would look to the new MAF sensor not working properly for the car.
Or a fuel delivery problem. Stalling as you try to increase RPM is a sign of not getting enough fuel.
Stalling can happen from to much fuel but it takes alot.