Car was sputtering on highway, now worse, driver relays click very fast,vehicle death

[jt1583]

A few days ago I had some sputters and hiccups on the highway, thought nothing of it, although it was a new issue. Then I went over a transition on highway and it seemed to coincide with that so I thought it was physical (ground or sensor wire maybe).

When I started it today, the relays at the driver footpanel were clicking very fast, and when the ones down by the ECU started clicked the car died. I don't think it's the relays themselves, because even if I swap them around, they still click, very fast. It seems either ECU related or power supply related. What are the ground wires to check?

I pulled the codes, getting

14 - speed sensor
34 - knock sensor
41 - intake air temp
82 - crank position
105 - EGR

all these are correct except crank position, which I've read is monitoring only. The other sensors actually are missing for the most part.

It's a 95 S14 with a 3C ECU and pretty stock KA24DE. Fuel pump seems to be priming and running okay. Everything under the hood still looks tidy although this could be a grounding issue. No multimeter available to check battery/alt status, I'll work on that.

Any advice very welcome, thanks in advance.