For anyone else reading, I just spoke to a dealer selling a 93' XF. The 93 actually does still have the 4.1. Its the 94 and 95 XG's that have the motor that EA2 mentioned.
There was a number of reasons why Ford stayed with the XF Ute and Panel Vans from 85 till 93.
1, Holden had no ute or PV at that time some there was no competition
2, They had a whole SHITLOAD of 4.1 litre engines and nothing to do with them all.
3, The XF Ute and PV was very popular and sales showed no signs of slowing down
4, The AU was a piece of shit and no tradesman would buy one
. (I didnt make that one up I read it somewhere =).