had the same problem on my 88 Volvo
Would just cut out & it was dangerous.
Last time just died on the road & I had to coast to the side & up a curb to get off the road. Luckily no accident

They figured it was the fuel relay & replaced it & that fixed it

Glad the contact clean worked w you.
Those things are $50 bucks or so.
Still the car was 20 years old & relays don;t last forever