Jaguar xj12 HE 1984 misfiring

[davesjaguar]

Morning hope this is the correct page for asking questions. Could someone please advise me on how to test the following parts with reading I should expect

Throttle positioning sensor which pin to test

Lucas AB14 electronic ignition amplifier

Correct readings I should expect from the 2 x coils

Regards
Dave

[mike020150]

You don't say why you are suspicious of these particular components. Have you eliminated all the possibly more common causes of misfires, induction air leaks and any from the many vacuum components/lines?
Unlike PRE HEs, throttle switches on HEs are simple potentiometers so any readings should be progressive voltages as the throttle is opened or closed.
Disconnect the distributor pick-up to ignition amplifier leads and check the resistance of the pick-up. It should be 2.2 to 4.8K ohms. Reconnect the leads and measure the voltage between the battery positive terminal and negative terminal of the main coil. it should be zero volts with the ignition on and 2/3 volts during engine cranking. If not, the amplifier is at fault.
Unplug the leads from the negative terminal of the main coil. There should be 12v present at the negative terminal when the ignition is on. 0v indicates a dead coil. Reconnect the leads and check 12v is showing at the main coil positive terminal. Less than 11v means there's an issue with the ignition switch or wiring. Complete the same tests on the secondary coil.
I hope these suggestions help the diagnosis. Mike.

[davesjaguar]

Thank you so much for your advice I will check them out later tonight.