I unplugged the two computer modules on the passenger's side (US) footwell to look for any corrosion, plugged them back in and now the car won't start.

The car started and ran before and this was all that I did.

Is there a reset procedure I don't know about?

If so what do I need to do.

 

Check the fuel cutoff inertia switch by the passenger door. It’s very likely you shook that enough to activate it. Just press the button, and try starting it up.

 

I already checked that and it doesn't seem to have tripped.

 

This car will be fixed easily, sold dirt cheap or towed to the junk yard. I am tired of dealing with the Jaguar electronics, rough idle, cracking manifolds, bad coils, and every other issue that gives these cars "character".

 

I would check the pins inside the two connectors of the ECU carefully and see if any has fallen off or is bent. I would also check if the all the wiring cables to and from the connecting plugs are in good order and the plugs and the connectors seat properly.

 

Ahh yes, I did that one time. I bent one of the pins... very obvious to spot. Simple, but careful to fix with some needlenose pliers.