good day fellow ford owners, I have just purchased a 2006 magnet xr8 ute with a 6 speed auto with 200,000km. I am having an issue with fuel surge. At 80km the revs fluctuate about 300rpms. I drove 4 hours home the day i purchased and couldnt fault any other issuse except the alternator is charging at 13v.

No dtc set, replaced, coils, plugs, all 4 o2 sensors, fuel filter, pcv and purge solenoid hard lines and connectors under manifold, new rocker cover gaskets and intake manifold gaskets. Have removed and inspected cat converters, replaced throttlebody with known good one and tps sensor. i have cleaned all engine grounds and replaced both battery terminals.
Shrtftb1s2 (%) showing n/a
Shrtftb2s2 (%) showing 99.2

hopefully someone also has had this issue and can help me out.
Thanks

Have you looked a fuel pressure or tested the pump? 200k on the original pump means it's probably knackered. PITA to change but I cut a hole in the floor and made a hatch for my Pursuit that had a dead pump.