I keep getting the EPC light on a cold engine, throttle at idle or about, going 25-45 mph or so, within two minutes of driving away. If I turn car off and back on, all is normal for a couple days to a week. I replaced the sensor and all was good for a few weeks. Today was a check engine light, knowing this has happened enough time to warrant it. Car runs just fine otherwise. What to do next or in the first place? *Edit- I want to mention I’ve had this same thing for bank one as well. Both slow response. Only exhaust cams.
I don’t think it’s a sensor problem. You get that particular code when the actual cam shaft position doesn’t match what the car is looking for. I think it’s not unlike VANOS solenoid issues in BMWs. Try to snag a VVT solenoid sometime soon. If your cam shaft isn’t properly activating VVT I think it will at best do nothing but reduce performance, at worst, some parts of your engine that shouldn’t meet just might have a one night stand.
I’m not a mechanic, just an enthusiast who knows how to narrow down issues after owning 3 N54’s. I may be incorrect after all, so good luck.
I replaced both of those in February. Maybe I should have purchased from a more reliable source. I’ll look further into them. Oil level is right and in good condition also.
Do you change your oil at the Audi recommended interval or more often? The actuator can get oil sludge built up inside it. Changing the actuator is an engine out procedure, or the engine needs to be dropped at least 10~12".
I get the same thing. I’ve just bought 4 oem sensors today. Haven’t installed them yet. I hope it gets rid of it. It doesn’t come up all the time, but it’s intermittent
Ps. Nice colour rs 
I had this as an intermittent fault I changed all 4 sensors and I’ve never had it since. I didn’t need to do all of them but I thought I might as well.
There fairly easy to fit you just have to bend the heat shield out a bit to get the lower ones in, the top ones are easy to get too.
I change it between 5k-7500 miles. I use Molygen 5-40 and do the Liquid Moly flush every other change. I really hope it’s not an adjuster. I put 40,000 miles on this car last year, and at 98,0000 miles it just maybe time to get something newer. I have 2 c5 allroads that I want to make 1 really nice car. That is where I want my engine out money to go.
Edit- I have the other two sensors, so I’ll go ahead and swap bank one out as well.
I replaced all 4 sensors as I was getting a fault. No more fault.