loose lamda

[220bhp]

I had a look under the bonnet to try and sort a few things on my car, which has a flucuating
boost problem, and found the lamda was loose.I have had a few that would'nt budge but never one that worked loose.
Car is running better but still is not right,I need to sort the problems out so I can get the map tweaked at MRC after the rebuild as it now has a lower CR .and a 7a ex cam.
How much would running on the old map affect the way the car runs let alone with a loose lamda.

[prj]

No one knows what is in your last map besides your tuner, so ask your tuner such questions.
If the Lambda was loose enough to create an exhaust leak, then the Lambda readings can be off, and it'll run too rich.

[macspring]

Prj,

Is there a way to test the health of a lambda with a multi meter, or maybe vag--com?

Thanks.