lack of power 2.2dti
21. Aug 2011 at 14:43     my omega diesel seems to lack power lately im changing down on hills alot ,its had recent oil ,fuel and air filter change.I s there anything i can check ie breathers to clean out which would make a difference.

Well this could be a number of different things
.
Firstly check air filter condition and replace if necessary.

Perhaps obvious, but check brakes front and rear are not binding.

Is your turbo working correctly? Can you feel the additional power when the turbo comes in at about 12-1500 rpm under hard acceleration? If in doubt get a mate to hold onto the fat pipes either side of the inter cooler while you rev the car up. Normally these hoses can be felt to pressurise when the turbo boosts. Air leaks in these fat pipes or inter cooler will decrease effect of the turbo by  allowing air to escape.
The turbo is turned on by an electically operated vacume switch. Problems with the vac system would almost certainly bring up the EML and  store a critical system type fault code.

General condition of engine, mileage  and any other symptoms may also aid diagnosis.
Any codes stored?

As i'm sure i've mentioned before, check the exhaust silencers and Cat haven't collapsed internally. As Joff points out, EGR and Inlet are also points to check.