Hi everyone, I'd be grateful for any thoughts on what might be causing the following issue please:
2012 A4 Avant TDI (143 bhp)
Every day, when I first start my car and accelerate away, the car judders really badly and struggles to accelerate - almost like its struggling to pull fuel through. But then after about 20-30 seconds of driving (max), the juddering stops, and the car then drives absolutely fine with no juddering or acceleration problems at all... If I drive the car again later in the day, it doesn't seem to do it - its just that first cold start of the day.
It's been doing it every day for the past 4 months, consistently on first start up (with the exception of just a couple of weeks recently when it stopped doing it, but now its back again).
The car fires up no problem on first turnover, and it idles really smooth on the driveway. The juddering is worse when the car's pulling uphill, but it does it downhill as well. It does it in all gears. I've tried idling the car for 10mins first after starting it before setting off, but it still does the judder.
I've had it into my local independent vag specialist. They had the car for a couple of days, but couldn't replicate the issue, and found no fault codes showing. We couldnt fathom why it didnt do the juddering when they drove it, but did note one difference that they'd kept the car inside overnight (whereas I keep it on my drive). I'm not sure how that could be a factor.
The car's done 130k miles, gets serviced annually, and since the problem started, I've had the fuel and air filters replaced, and the egr valve checked (reported as operating correctly). I've run some injector cleaner through it, and switched to using premium diesel, but after 2500miles, the issues still there. It's not seemingly got any worse, but equally its not got any better...
I'm just not sure how to start troubleshooting it. Has anyone experienced something similar?