Bad ECM or ECM relay.
1991 jaguar jx6 will not start
The ecm module is located behind the passenger side kick panel. I don't know of an ecm relay.
behind the radio
i have a 1991 sovereign xj6 and i have the same problem, BUT the gauge would show correct levels when accelerating
Next to the battery.
Behind the glove compartment.
the ECM is located under the hood on the driver side fender it is in a black box i just replaced it
replace the ecm
It is inside the ECM Module
YES it is.
The ecm (engine control module)