Hi guys. So I have had a couple problems with my 2011 Audi A4 sline. Whenever I am idle, the car shakes and the rpm needle will dance between 900-1000. The car is also very jerky in 2nd gear when rolling, and in 1st gear it stalls. The shaking wasn't so bad at all for the past month. Took it to different mechanics on 4 different occasions. They plugged a computer in and had 0 faults. Couple days ago, I called my usual mechanic to ask him to at the very least inspect my injectors. He said I have nothing to worry about again. Today when driving back I experienced the problems above. Car was serviced 1000km ago so it's not a matter of filters or old oil etc. If anyone has anything to help it would be greatly appreciated, thank you !

It certainly sounds as if it is not firing on all cylinders. The usual culprit would be the injectors, but the absence of an error code puzzles me.

How many miles has the car done? Does it drink an excessive amount of oil? Is the exhaust smokey?

26 minutes ago, cliffcoggin said:

It certainly sounds as if it is not firing on all cylinders. The usual culprit would be the injectors, but the absence of an error code puzzles me.

How many miles has the car done? Does it drink an excessive amount of oil? Is the exhaust smokey?

Thanks for the reply! The car has 269.000km (145.000miles i believe). Oil is always fine, and the exhaust is perfect. I was suspecting a vacuum leak or a faulty MAF sensor, or PCV valve. I have taken it to the mechanic today for an in-depth check, it has been 7 hours since and no update so I'm hoping it's nothing too serious... 

4 hours ago, cliffcoggin said:

It certainly sounds as if it is not firing on all cylinders. The usual culprit would be the injectors, but the absence of an error code puzzles me.

How many miles has the car done? Does it drink an excessive amount of oil? Is the exhaust smokey?

I got a call back from my mechanic, he pinned it down to either the fuel pressure regulator or/and sensor. I was thinking either MAF, throttle body or pcv. I'll find out more tomorrow when he does further testing

UPDATE -- It has been fixed!!

The problem was the fuel pressure control valve (PCV) along with the fuel pressure sensor. It was a 500 quid job. After reinstalling new parts, it worked like new! Power restored, better fuel efficiency and no more jerkiness in lower gears along with no more rough idle/shaking!

Your mechanic sounds like a good man to know. Solving that problem without error codes means he used his brain rather than a computer.

4 hours ago, cliffcoggin said:

Your mechanic sounds like a good man to know. Solving that problem without error codes means he used his brain rather than a computer.

Well, after picking the car up, I got a check engine light. He diagnosed it again and the error code P0190 came up, for the fuel pressure sensor. That is the part that was replaced. He turned it off and removed it. This morning, when heading to work my check engine light popped up again. The initial problems I was having were gone, bar some minor shaking when idling the cold engine that seem to go away once the engine is all heated . 

Hi having the same issues with my 09 sline changed two sensors on the rail also mass flow fuel filter etc still no joy done a leak off test on injectors found one was empty two where the same (middle of tube)and one filled the tube and now going to get a injector but not sure what one to change full one or empty one and still don't know if it will sort good luck Mark 

On 10/20/2024 at 9:27 PM, Murphe said:

Hi having the same issues with my 09 sline changed two sensors on the rail also mass flow fuel filter etc still no joy done a leak off test on injectors found one was empty two where the same (middle of tube)and one filled the tube and now going to get a injector but not sure what one to change full one or empty one and still don't know if it will sort good luck Mark 

I also found out that one of my injectors is apparently over fuelling ever so slightly, such a small bit that it's not worth getting changed just yet. It's still good for a good bit but will need changing eventually. It's still gonna be a hit or miss since it's gonna be 1 new and 3 old. Injectors are a delicate thing on TDI's but hopefully we both get it fixed 🙏