On a couple of recent trips away, the fuel consumption of my 2001 TD Jack has risen quite a bit. Previously I would get 600 km + from a tank full of fuel. (cruising between 95 - 105 km/h, no cruise control) However,on two trips in the past two weeks, I only managed 450 - 500 km from a similar amount of fuel. What consumption do other 4JX1 owners get, & does anyone have any ideas on things to check/fix to help with better fuel economy ??? 
The vehicle is in good mechanical condition & is serviced as per the manual. Tyres are 245-75 - 16 at good pressure. Engine is standard but with EGR blocked off. 2&1/2 inch exhaust from turbo. The vehicle still runs well with no noticeable drop in power.
The only change since the increase in fuel consumption is the replacement of the intake TPS as in previous post.
The new ITPS was not set with a Tech 2 / scan gauge, but people more technical / mechanical minded than I said it was not necessary, as long as it was as closely positioned as the old one was. ???
Any ideas greatly appreciated
Regards, Russell .......