not running below half a tank of gas?

They didn't make an R8 in 1994, so I assume you mean R8? Anyway, if it does run with a 1/2 tank of fuel it means the fuel pump is getting weak or the fuel filter is clogged. here is the location of the filter and I have left instructions on how to change the fuel pump out in the images below. Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.