03 vrs lumpy between 1500 and 2000 revs. Any ideas? Have tried shop bought fuel injector cleaner which made minimal difference for a short while. Just stuck wondering if the injectors might need replacing and if there is any way of knowing for sure?

Cheers for any advice

Fault code check would be a good start, check all vacuum pipes and hoses etc.

Clean the throttle body too

As Bodge said remove & clean the throttle body. You'll need to get someone to press the accelerator or prop something up to keep the pedal down so the throttle butterfly is open to clean it properly.