BARO errors Unstable flight

[attachment=1]logImage10-06-15.jpg[/attachment]

[attachment=0]BarrologImage10-06-15.jpg[/attachment]

Hi I am new to all this and have just built my first quadcopter. I am having an issue and would appreciate some help with.

Using an APM 2.5 getting barro-0 barro-2 errors in logs

When first start all seems fins hovers stable in position hold mode, after about 5 mins it starts wobbling and tries to land.

I thought it might be prop wash affecting the barometer so i covered all the holes in the case with tape and get exactly the same problems.

I do have a sonar attached but cant find it in the log…