Audi A4 rough idling

rockoman

Hi,
     Ive had issues lately where by my Audi when idle has aggressive roughing with the RPM needle bouncing over the 1000rpm mark. When cold it is quite severe and cuts out occasionally, after engine warm up it performs slightly better but still rough idling. I have taken it to my local garage in the Celbridge area but they found it hard to diagnose as there was no check engine light. I inspected the throttle body and there appears to be a lot of carbonization on the valve although not the root cause I believe. The first time I brought it to them they cleaned the Airflow sensor and worked for 2 months. The second time they replaced the filter pump and ran fine for a month and started reoccurring, i also noticed when I got the car back the fan and AC was quite weak, so Im guessing they adjusted the settings here too to mask the problem.
So as you can guess I've lost all confidence with them and money to boot, I would suspect there's a problem with air intake, like the injectors or DFP?
Anyway suggestion welcome, but more importantly a good Audi mechanic in the Celbridge, Leixlip, Maynooth Area????

Car99

Is it very smoky while rough idling? Is it using more oil than normal? What engine ? What mileage?

rockoman

No a little smoky but not burning oil, have needed to top it up this year

rockoman

Sorry haven't needed!!

rockoman

2009, 1.9 TDI 136 BHP,
 Miles:140K

Car99

Could be the injector wiring loom , not that expensive from audi and easy enough to fit. Cheapest option to start with.

rockoman

Would that cause the engine to dip RPM's like the engine isn't getting enough of air? I do think that the chamber itself may benefit from cleaning with the likes of Terraclean as over the years there might be quite a bit of carbonisation. Have you used this before?

http://www.terracleanireland.ie/index.php/agents

Lord Nikon

I had a previous problem with a Skoda Suberb, no fault codes thrown up, but felt like injector problem, rough idling. Even after full decarbonization and turbo clean problem persisted. If you get the head taken off, check the camshaft isn't bent, that was the problem with mine.

Zero-Cool

Having the same issue with my i30, will check the camshaft thanks.

"Check the camshaft"

Lord Nikon

Zero-Cool wrote: »

Having the same issue with my i30, will check the camshaft thanks.

"Check the camshaft"

Crash Override.