Sometimes when I start the car the gauge cluster shuts off and stays off for for a few seconds or more. All the gauges go to zero and the choke releases. Within a few blocks of driving everything usually works normally.

This has been happening only occasionally for the past 10 years but three times today. I've changed all the fuses but don't know what else to try. The only electrical problems that I have had in years past seem unrelated: upgrade to 70 amp alternator, replaced fusible links with block fuses, added relays for headlights, and replaced battery cables. I know that there are a lot of electrical problems with the 1st gen but I've never heard of the entire gauge cluster shutting off.

1981 RX-7 with 300K miles. Any ideas?