On a 1993 XJ6 the fuel filter is bolted to the underside of the car on the nearside near the rear wheel-arch.
The primary fuel filter will be in the boot, "Trunk". At the front right corner of the spare tire compartment.
Usually about 19 MPG
The fuel filter is mounted in a retainer on the frame near the left rear tire, it is an inline style fuel filter with a compression (flair fittng) nut on each end. Make sure you replace the two "O" rings when replacing the filter.
in the gas tank
87
in the trunk remove the spare tire
o2 sensor fuel too rich
I believe it is 36 psi. Beez in Delaware
Ignition Amplifier Failure
The fuel pump relay for a 1993 xj6 Jaguar is located in the trunk on the right hand rear side, next to the rear light control module. It is a 4 prong black relay.
Fowled or faulty fuel injectors. Replace or repair.