XJ6 runs only briefly

[Henry Lanford]

I am brand new to the group. Thank you.

1986 XJ6 van den plas

Quite suddenly developed this problem.  It starts promptly and runs for a couple seconds and stops.  If I retry right away it might start for what I think is a briefer time but often will not start again at all - until much later.

I thought  the problem could be the AVM not turning the fuel pump on with airflow, but that was wrong: if I move the plate in the AVM - with ignition on - the fuel pump does run.

At the moment I am stumped.

[LairdScooby]

If you open the throttle does it keep running longer?