AdrianEagle

This is a known symptom of MY04 and MY05 models. Loss of power during hard acceleration at high revs.

Map sensor was (is) replaced by new unit and problem disappears.

It is not done on recall but by customer complaint.

Go see your dealer.

trebor

This doesn't sound like a Map sensor issue to me!

I had map sensor problems a few months ago - wacking it does work, but is really only temporary (also disconnecting the Map sensor and connecting it again can work) - I got mine replaced under warranty but I think it only costs about

MB

If it was poor fuel it would be present at any point?

AFAIK the lambda controls fuelling (with some MAP input) below VTEC. On VTEC the lambda becomes passive and the MAP governs fuelling - ECU goes into open loop control. I m open to be corrected here.

MAP is used to calculate engine load, so it can affect VTEC engagement in theory?

I cant believe people are hitting the sensor though I have seen the equivalent sensor destroy engines on a Subaru. Ok, they are more critical on FI but its not a good idea!

MB