I don't know about the airspeed or the altimeter, but you might want to try
something with the attitude indicator.  Before turning on the battery, cage
the attitude indicator.  Leave the attitude indicator cage until after your
run-up.  This will give the unit plenty of time for spin up.  Additonally,
when you go to shut down, cage the attitude indicator.  This will allow for
the attitude indicator to last longer, additionally you might find that it
works quite well.
 
  These type attitude indicators can take a significant time to spin up if not
caged.  Sometimes on the order of hours!  We have one in the ES.  Following
these steps, it works really well.  If you don't do this, I have flown for
over an hour without it fully following my attitude.
 
  Try it.  You may have something else wrong, but this has worked out well for
me.

Do you have the correct tilt applied to your AI? Mine came with the wrong (8 deg.) tilt. Would always fail in flight swapped out for 0 degree tilt... no problem.

 

Jeff Edwards

LIVP N619SJ