I have a 2003 3ltr turbo diesel ute that goes into limp mode after being driven for less than afew minutes. Whilst the veichle is ststionary it run s fine and does not go into limp mode. We have replaced three engine sensors and checked wiring and fuses to no availe. Does the computer on this veichle have a sensor on the spedo or gearbox? Also could it be caused by the thermostat being stuck open or shut.
Had the same problem myself - throttle position sensor showed faulty. Although the TPS is a sealed unit, I managed to get it apart and found moisture on the potentiometer. Clean it up, dried it of, glued it back together and away we went - for a week. On retesting the idle setup, the TPS was found to slightly mis-adjusted - reading around 0.6v then dropping slightly as the throttle was opened, then rising. Set it up with idle at the lowest possible voltage and risng voltage only as throttle is opened.