Hi Max
pscan has three different ways to access the engine ECU on a V8.
1. Engine ECU, sub menu V8 260, protocol Ford.
2. Engine ECU, sub menu V8 260, protocol gateway
3. Engine ECU, sub menu EOBD, protocol Ford.
Please can you try all three, after each one turn off the ignition, wait 30s, then switch on and try the next?
I have only had access to a late model ZT 260 to develop this.