Can anyone help -my Astra SRI (X20XEV) seems a bit sluggish if I boot the accelerator hard (at stand still in neutral), the engine seem to pause for a sec or two before picking up the revs. The idle is fine/ no strange noises/no management lights/plus fine on the open road and also just had a MOT and past ok. Is this normal at stand still as I am sure it was better than this a few months ago? I have had no mods done. It seems there is plenty of air going in, but perhaps not enough fuel?? I have had the air tube off at the throttle body and can't see any damaged pipes.