[Injuneer]

Its -4AN.

I don't know the exact layout for the 93 hard lines, but on my 94, I used an NOS #17535 -4AN 90-deg swivel fitting on the Schrader valve, ran a short -4AN hose with a 1/8" NPT male on one end, and used a 1/8" NPT brass coupling from a hardware store to connect the pressure sending unit to the hose.

The advantage of using the hose it that it allows you to tuck the pressure sending unit out of the way, like behind the PCM, and keeps the load off the Schrader valve, which is easy to break off the hard line.

The 90deg fitting helps on the 94 because it points the connection to the side rather than straight up at the cowl, and the swivel allows you to aim the hose in the direction you want. Not sure if you need the same on a 93.

NOS sells hoses with -4AN on one end and 1/8" NPT male on the other, but they are espensive. I've seen custom lengths on e-Bay for about 1/2 of the NOS cost.