Are you using cheap supermarket fuel? Use decent fuel such as BP Ultimate diesel, and/or Shell V-Power diesel. They contain cleansing additives.
When you clean your shower head with a limescale remover, you see a big improvement in your shower spray’s performance. It is similar with new Shell V-Power fuels; by helping remove built-up deposits that have already formed on the intake valves and/or fuel injector nozzles, it helps to restore your engine’s performance.
My Golf has done 145,000 miles with no problems on these fuels. Better mpg too. Cheaper in the long run.
Chicks Fan
August 2017