Evaporative canister purge control valve circuit fault
Fuel Fail 37 is either a fault with the EGR Valve or its Solenoid
Ignition Amplifier Failure
I own a 91' XJ6 also and i believe when that code comes up it is as simple as your gas cap not being on all the way
Fuel Fail 47 Idle speed contol valve - coil 2: Open or short circuit.
1991 jaguar jx6 will not start
This means Idle speed control motor (ISC) or valve
Fuel fail 39. EGR circuit. Faulty system operation. Is on my 90 xj6 as well- going to take EGR valve off and clean it- see what happens.
Usually about 19 MPG
in the gas tank
87
fuel 44 is heated oxygen sencer bank A other term lambda senser the jag has two.