hi, I have an Audi TT (1.8t AJQ) which has worked well, with

- self-made software (injectors ev14 0280158124, mild "stage1" and just other little tweaks, n249 delete and pedal response changed little bit).
- I note that this error is easily repeatable, not randomly occurring.
- It starts when I start the car that has been standing still for a long time (engine cold) and drive approx. 9 km or 7 minutes. Car starts to "freeze or stall".

I have a mixture meter from which I can see that if I press the gas, the engine goes leaner, in addition, I feel that the engine is shaking. I stop the car, I notice how the car is running really shaky, probably not on all cylinders, the mixture meter still shows close to stoichiometric, but the running shakes. I gently throttle it in place, and it revives in minutes. After that, I can drive all day long until I do the same thing, i.e. I have to start with a cold engine. The car is almost standard except for the injectors and re85 flexfuel kit (ethanol with sensor). The problem started without making any changes to the car. It starts and goes very well when cold the first ~7 minutes. The amount of ethanol doesn't seem to have an effect, I tried normal gasoline, as well as 50/50, exactly the same symptoms, no effect. In the logs, the error starts when the "rpm" graph starts to show a zigzag.

Injector seizing or coil dead.

Another fault replaced it.

Lambda sensors die (fault code from circuit, front o2 sensor voltage too high or too low). Now the third one is put in and it also started playing tricks. In addition, full acceleration is sometimes slow.

Often during wot acceleration the car feels really lazy. Log attached. Doesn't always happen but sometimes.


Fuel pump is Sytec 342em and FP raised to 5bar.

What do you think?

There is strange happenings on MAF, o2, injector duty cycle? reason?

I cannot know in advance when this fault will occur. Makes it difficult.
I want you to pay attention between 2499 and 2506, at least:
rpm / maf / tevfagke_w / o2s voltage / lambdacontrol

Shouldn't there be lambda control during wot??

But still it is because the o2 sensor varies lean-rich?

However, there is no ignition retard or anything else that would indicate that it is running lean. Should the o2 sensor correction work during wot? I have been of the opinion that there should be no matter what oxygen sensor says during wot? Am I wrong?