Edelbrock 91004

[TheUncle]

Hello,i do have a Edelbrock Data 91004,
this unit worked well over the years,but now it fails.
The last season the box started to a sporadic recording from 100,80,60 40 20%
until nothing goes.It only works at idle when warming up.During racing nothing is recorded now.
We changed the battery,same result.
All cables in the surrounding area are shielded.From the data box to my ignition box (MSD Digital 7)
are 110cm,so should there be no interference.
Does anybody can help to find out why the box fails?
Thank you for helping
Greets TheUncle