Hi everyone,
I am new to this forum and could do with some help if possible.

I have a 2006 focus 1.8 tdci sport
And I have noticed that when the car is parked up and I rev it just over 1000 rpm the engine and car shakes like a bad misfire but its not a misfire and when I'm driving it holds back briefly at 1500 rpm.
Apart from that the car runs and drives perfect no engine lights on or warning lights

If anyone could help my I would be truly greatul

Many Thanks