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

[porschefan76]

Originally Posted by blue62

Looking at the post Cat O2 signal I would say your cats are not working.
Post Cat signal is following RPM and Pre Cat signal very closely. Not as it should be.
Post Cat signal will have some rises and falls with RPM and engine load but should be biased towards a flatish signal voltage in the .650-.750 mil volt range.

There are some good youtube videos on testing for exhaust restrictions.
Also if you look up ScannerDanner on youtube he has some very good videos on reading fuel trims and O2 signals to diagnose performance problems.
He is a professional and very good at what he does.
You can view his videos and have a visual of what your Post Cat O2 signal should look like (flatish) under different running conditions.
Perhaps some of his videos will give you some insight on your issues.

OK, I'm going to follow this and see where it leads. I've watched Schrodingers Box on youtube and he's where I got my primer on fuel trims, but ScannerDanner seems great as well. In fact, I'm watching this video now:
https://www.youtube.com/watch?v=9TlygJMxTps
I may go purchase a back pressure gauge and check each of the cats. The only hesitation I have with this right now, is that in ScannerDanner's video, he said that because the pre-cat O2 sensor indicates rich at wide-open throttle, he'll focus on the exhaust and assume it's not a fuel issue. It does not appear that I am running rich (likely lean) above idle. I also do not have a situation where the car will not exceed a certain speed. It still "almost" drives like it did before above 3000 RPM. Additionally, my water temperature gauge has never indicated that the engine was running hot.
I may start by checking the temperature of each cat at the inlets and outlets and ensure the outlet temperatures are higher than the inlet temperatures, indicating the cats are heating the gases. I will also try to capture a stream of good Durametric data from all 4 O2 sensors while maintaining 2000-2500 RPM for a minute or two. I will post results once I get a chance to run these tests, hopefully this afternoon. Thanks!