VW Scirocco Diesel: Power Loss and Cold Start Issues

I had a similar issue with my 2012 VW Golf diesel. Being someone with some hands-on experience working on cars, I initially tried to diagnose the problem myself when I noticed the same symptoms, rough idle, increased fuel consumption, and especially that characteristic power loss during cold start. After checking the basic stuff, I took it to my regular workshop. The mechanic found that the cable connection to the fuel filter heater was damaged, which was causing intermittent electrical issues. This explained why the fuel system wasnt working properly, particularly during cold starts when the heater is most needed. The repair was straightforward, they replaced the damaged wiring and connections, which cost 95€ including labor. Since the fix, the diesel engine has been running smoothly, cold starts are normal, and fuel efficiency is back to where it should be. Before I can provide more specific advice about your Scirocco, it would help to know: How many kilometers has the car done? When was the last fuel filter change? Are there any other warning lights besides the engine management light? Does the problem get better once the engine is warm? These details would help determine if youre dealing with the same issue or if theres something else going on with your fuel system.

Thanks for sharing your experience. At 77537km, I am also dealing with similar symptoms. After your reply, I checked my service records and realized the fuel filter was never changed since purchase. The power loss does improve slightly when the engine warms up, but the rough idle persists throughout. No additional warning lights besides the engine management light you mentioned. The fuel line and connections look visually ok, but I will have them inspected properly. I appreciate the tip about checking the wiring to the fuel filter heater. Your repair cost sounds reasonable, hopefully mine will be a similar straightforward fix. Would you recommend getting the fuel filter changed regardless of what they find with the heater wiring?

Thanks for those extra details. Since you mentioned the fuel filter has never been changed in 77000+ km, I would absolutely recommend replacing it alongside checking the heater wiring. On my Golf, I learned that a clogged fuel filter can cause many of these symptoms, and its actually a recommended service item every 60000km. The fact that your engine runs better when warm but still has a rough idle points to potential issues in the fuel delivery system. When I had my repair done, the mechanic explained that old fuel filters can restrict fuel flow and cause engine stalling or poor performance, especially in diesel engines which are more sensitive to fuel system issues. I would expect the total cost for both the fuel filter replacement and checking/repairing the heater wiring to be around 180-220€. The higher fuel consumption youre experiencing now will probably offset this repair cost within a few months. After my repair, I also started following a more regular maintenance schedule for the fuel system components. These preventive changes have helped maintain good fuel efficiency and prevent similar issues from recurring. Make sure to keep your service records updated after the repair.

Thanks for the detailed explanation. Your suggestions make a lot of sense, especially about the maintenance schedule. I will book the car in next week for both the fuel filter replacement and heater wiring inspection. The 180-220€ estimate seems fair considering the work involved. The rough idle and power loss have become quite frustrating, particularly during my morning commute before the engine warms up. Getting these fuel system issues resolved will hopefully put an end to the engine stalling and performance problems I have been experiencing. I will definitely maintain better service records going forward and stick to the recommended 60000km interval for fuel filter changes. Preventing these issues is clearly better than dealing with poor fuel efficiency and engine performance problems later. Let me update the forum once the repair is done to share what they found and if it resolved all the symptoms. This information might help others with similar issues.