I have a 99.5 A4 with a 1.8t AEB in it. I'm pretty new to my Audi but am decently mechanically inclined. This P1136 code is giving me a lot of grief lately. When it first came up, I researched it and started looking for bad check valves, which I found. After replacing those, it came on again. I kept searching the car and found a loose line between the FPR and intake manifold - replaced it - light came on again. One thing I've noticed is that when the CEL does come back on, it's when the car is all the way at operating temp. and the car is just idling. Now, it does take some time for my car to get all the way up to operating temp., according to the gauge. I could go a whole day without it ever reaching it - it just depends on the weather. The last time it came on, a full 24 hours after I reset it, it was about 90 degrees outside and I was in a lot of stop & go traffic and then had to sit for a train - it came on while I was waiting for train. I do not notice any difference in how it drives or responds. It is driving me utterly crazy! I've spent days under the hood trying to find the leak. I've taken my MAF out and did a physical inspection and it looks to be in good working order. I tried someone's advise and tried running the car with the MAF unplugged to see if there was any difference. While there was no difference at idle, it was a lot slower in responding when I pressed the gas pedal. I do not have VAGCOM and don't know anyone who has access to it, other than the dealership. Any suggestions from anyone would be greatly appreciated and definitely taken into account.

I should mention that P1136 is the only code that comes up. After each time it came back up, I rechecked the system and every time it was the only code popping up.

 

Same engine in my A4, 1997. Your symptoms sound very similar to things that have happened to my Audi. My P1136 was due to MAF and also a broken hose from intake manifold to diverter valve. Could be o2 sensor sending bad signals, too. I had rough idling, which disconnecting MAF fixed so I knew that was the issue. As for not getting up to operating temp, a new thermostat fixed that. Mine failed open so I had coolant running through a cold engine. All these are pretty easy DIY repairs. Good luck.