My 1993 4/4 had fuelling issues due to a failing pump.
I replaced it. At the same time I did some tidying up. Drained and flushed the tank. Fitted new flexible pipes. Fitted a filter between tank and new pump for protection. New main filter under the bonnet.
I think the pump was affected by some bits of crud from the tank. Electrical contacts all cleaned up..
Due to the age of the car I decided to do the non pump jobs as a belt and braces exercise. The engine running issues disappeared.
It got me thinking....I put new ignition leads on later as the old ones were originals ( looked like it anyway).
The leads were standard from eurocarparts. The pump was a Bosch...the most expensive bit to buy (£50 -ish).