Baron G58 woes

[lcomer]

So I was doing an ILS flight. At 5,000 ft the main glass cockpit went out to lunch. The GPS screen still worked, and I could use the NAV button to fly the selected route. I had to rely on the old altitude and airspeed gauges, but all other info was wacky. Strange thing, when I descended to 2100 for the ILS approach at the airport (turned alt hold off and used the VS to descend), everything came back on line? Still wish they had a gauge for the prop RPM.