[V8] Surging saga continues

[aukdav]

Having some teething problems with my recent find.  1990 V8Q  When I picked it up it had moderate surging problem.

A read of archives told me 02 sensor was to blame.  Changed the 02 sensor with the tried and true Bosch generic.  No improvement.

Checked the #5 fuse, it was fine. 

Changed the fuel filter, no improvement.

Changed the NTS sensor on the back of the left head.  No improvement.

WOT gives good smiles.

What is the next step?

Thanks,
Dave