When updating my RV6 with GRT, I was told that most of the probs with the pressure senders is caused by the ground going thru the case. I soldered a tab to the case of each and ran a ground wire from that tab.
3 years and no problems.
Super Sabre Society
1993 RV6A, 1947 Cessna 140, in progress
2018 dues exempt but paid anyhow