1.9 TDI fabia 51 plate running lumpy

A few weeks back I noticed a little lump in the revs , 2000 rpm ish

Just a slight flutter , once passed this all was ok 

No black smoke and runs steady on tick over

Now today she's running very lumpy 

Feels like she's only running on 3

Still no black smoke 

And once you get going she's ok ish

So what's your thoughts ?

Injector loom ?

Dodgy injector ?

Pump ? 

Where to start ........

Edited 22 December, 20187 yr by Proheatpaul