I am still dealing with the CEL from this old thread. Something that is consistent is that when I run the car for a long time on the highway or drive it for a couple of days, I can watch my AFR guages and one bank will always start to move away from the other one under light load or idle from mid 14s to 16-17 and higher.
The second I clear the CEL, the AFRs immediately return to 14.6-14.7 solid on both banks at idle. Within a couple hours of engine run time one bank will start to creep higher and higher. Idle will become less smooth and the P1145 comes back again. Reset...back to identical AFRs and perfect smooth idle.
I've been going through this for over a year now and I'm thinking it is the ECU. If you read the other thread you can see that I replaced everything in the book that could cause a p1145 including the lifters! What else could make this happen but faulty adaptation calculations making one banks idle/cruise AFR consistently go lean but return to normal immediately after resetting the CEL which I assume clears the learned adaptation.
If it were something mechanical, wouldn't the problem occur in the opposite direction...it would be mismatched after clearing and then adapt to the same AFR?
All my plugs look clean and identical with no signs of incorrect mixture.

 

Easy to check: find someone who can lend you an ECU and copy yours to it. That's not too difficult if you know what to do. I can and would do it, but we are a couple of thousand miles apart

 

for my understanding something is wrong with your oxygensensors......do you have a log from the 02 Sensors at the moment your AFR fails? From all 02 Sensors!

Take care that the O2 sensors are not interchanged?

 

All 4 have been changed, the pre-cat pair twice and no they are definitely not interchanged Like I said, anything related to the CEL has been addressed. It still comes back. That's why I suspect ECU at this point.

 

i understand ...did you try to drive your car with disconnected O2 Sensors ?

does the issues come with disconnected O2 Sensor ?

of corse it is possibile that the ecu has a failure

 

This isn't like a MAF sensor problem where disconnecting it will show an immediate result. The car won't run properly at all with the O2 sensors disconnected and that won't help diagnose anything.

 

I have seen this with exhaust leaks

 

Second that - especially if your leaking at the turbo housing / chra

 

Please clarify, you've seen the p1145 with exhaust leaks? This is the number 1 cause of p1145.
Or did you see the symptoms I wrote about caused by an exhaust leak?
Thanks for any input.

 

P1145 cell because of exhaust leak. I didn't research into afr at the time. Like you I thought it was lifters. But redid my exhaust and the issue went away.

 

I can and would do it, but we are a couple of thousand miles apart

 

When you say "redid my exhaust" do you mean that you tried another exhaust, or remounted yours with new seals? Since this started, my engine has been out multiple times and every time new seals/gaskets were used everywhere but this strange problem persists. I haven't tried putting on a different exhaust yet.

 

when you reset ECU it comes back to normal, because ECU is re-learning the codes again.

throwing some ideas: try to inspect the headers, maybe you have crack somewhere, are you using aftermarket headers?

 

Stock headers, no cracks and new gaskets.

It is my understanding that when the CEL is cleared the adaptation is also cleared. I see this happening, and the instant I clear the CEL, the AFR on bank 2 which is always going lean over time resets to match bank 1 at 14.6-14.7.
Somehow, after driving for some time (usually 50-100miles) the second bank always starts drifting to an AFR of 15-17, and shortly after that the p1145 returns.
I guess I'm asking, how does the ECU cause the idle AFR on bank 2 to move higher after engine run time. That's what long term fuel trims are for aren't they - to compensate for small issues causing mixture problems? Or, am I looking at the whole thing wrong?
If there was a physical leak why would clearing the ECU instantly return the AFR to dead on perfect...wouldn't it be lean on the bank with the leak and then learn to put more fuel in the mixture to compensate? Mine is behaving exactly the opposite of this and I'm confused

 

yeah ecu is not getting the right reading thats for sure, Or like you stated could be ECU it self. I dont want to see old thread since im on my cellphone- I'm pretty sure you looked over everything- I hate finding gremlins myself,> I'm going to copy and paste more info here:

P1145

Oxygen Sensor Ahead of TWC, Bank 1 - Above Limit

Diagnosis conditions

NOTE: A lot of time is required (several days) until a fault is detected.

Possible fault cause
Valve lift fault
False air on the oxygen sensor after TWC
Oxygen sensor
Affected terminals

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NOTE
As this fault can be caused by a faulty flat-base tappet, a system test for a small lift has to be performed initially. The fault can occur sporadically; the test should therefore be performed at least three times when the engine is at operating temperature.
First indication of a valve lift fault can be provided by the adaptation values at idle speed (RKAT) and in the lower part load (FRAU) if they differ by more than 10 %.
Perform system test for small lift

WARNING: Test is carried out while driving. Have a second person operate the Porsche System Tester 2.

During the system test for small lift, the valves remain at small lift, regardless of the type of driving. Faulty switching conditions can be detected by rough running, just like with misfire detection.

Several cylinders may be stored as faulty, although only one valve on one cylinder is faulty.

In order to ensure that the fault is repaired, the flat-base tappets of the inlet valves of the entire cylinder bank should be replaced if a fault occurs.

A faulty flat-base tappet can be detected because the oxygen sensor FR for this cylinder bank enriches the mixture (FR > 1) during acceleration with wide open throttle, see drawing below. Difference from the other oxygen sensor > approx. 15 %. In the case of a fault, the flat-base tappets of the inlet valves for the entire cylinder bank must be replaced.

NOTE:
If a fault is detected, it is only recorded in the fault memory after 6,000 ignitions (at idling speed approx. 3 minutes waiting time).
It is important to observe the oxygen sensors during acceleration with wide-open throttle or to record their behaviour with the data logger.
Diagnosis/Troubleshooting

NOTE:
Do not use contact spray on the connectors to oxygen sensor.
If other faults (fuel supply) are stored in the memory, rectify these first
Work Instruction 1 - 2Click the image to open in full size.

NOTE: Do not exchange oxygen sensors ahead of catalytic converter and after catalytic converter.

Oxygen sensors ahead of and after catalytic converter