Have an E30 which has been for sale for a couple months and not driven... boosted it and let it run while I cleaned it up... took it out a couple times and it was running great. On my last little drive, I was pulling up to a stop sign, and the radio/speedo/tach/engine(not sure what if anything else) just quit. Pulled each fuse out and none were blown... got back in and it started and ran fine... (Although the radio had lost all its presets).

could one of the fuses just have been corroded a bit and removing/reinstalling fixed the contact?(is there one fuse that would control the engine as well?) Or is there something else that would cut out the power to everything, and then come back on?

Yes corrosion/loose battery cables. BTDT

HTH

Bob Duckworth