Hi. We have an isuzu trooper diesel that seems to be in safe mode, wont rev above 1300. We have drained the tank and put in fresh diesel, tried to check on machine, visual check on fuel lines etc.

This vehicle has a rotary injection pump and if its a 95 vehicle then no fancy electronics involved either so its either a fuel filter partialy blocked or the gauze filter inside the fuel tank ,if both of these check out as ok then the only other thing that would cause this a blocked air filter and check the air pipes as it could have a birds nest or a lump of rag inside the air pipes ,dont laugh or dismiss this --- trust me ---.also rev engine and check the air pipes are not collapsing,again seen it got the teashirt .Now if all this appears ok then its a fuel pump recondition job as the transfer pressure inside the pump is low and this is not a home job but an expensive repair ,cost here in spain is about 600euros and thats without the labour charge to remove the pump