If you've checked the oil level is correct then the next thing to do is do is check the MAP sensor connection and then do the MAP whack if that doesn't fix the problem.

A 'stuck' MAP sensor is a common cause of exactly what you describe or a feeling of 'surging' whilst in VTEC.

 

Same thing happened with mine, first thing i did was tighten up the Throttle cable which helped a bit, a new map sensor sorted the rest mate

 

Low oil level at all? I've heard that VTEC dumbs down if oil level is low.

 

Done that one, like I said reset the ECU doesn't cost a bean it that doesn't work then smack the map that wont cost either. Then start thinking about parts.

 

Vtec isn't dumbed down by low oil, it's disabled on oil pressure or inadvertently very low oil.

 

Treading carefully here

Might it be placebo & subjective to the driver as to how it feels?

To me sounds like a meet up with another owner to make a comparison could be in order

 

 

First few weeks of driving mine it felt brutal. And on occasion now it still 'feels' like lightening, all depends on how much the diesel you're overtaking puts his foot down out of spite.

 

When the MAP sensor stops doing its thing and VTEC stops working its very noticeable.

 

Thanks guys - it definitely feels like it's not doing the magic any more and flying like it used to so I'll check through the points suggested. Will have to come back and see if anyone wants to meet up for the purposes of scientific tests in North London otherwise!!