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There is NO substitue for removing the fuel tank, washing it out and cleaning it. A look around inside is about as easy as doing a tonsole inspection on yourself with a mirror...... you get the idea.
Its common over time with all our various grade fuels.. some we probably trust but so many that are bodgy... fuel pumps will fail in most any car.
The common issue at the time after budgeting for the cost of the pump and or sender unit.. is the labor to needed to remove the tank and rear suspension.. just to get to the top of the tank and do the 20 pump replacement itself.
There are lots of examples on the web of ways to cut an access hole.. but do it safely....do your reseach.. but here is a pretty well illustrated one from ls1tech https://ls1tech.com/forums/fueling-injection/1604846-98-racetronix-fuel-pump-hotwire-harness-w-trap-door.html