You should take another look-see under the hood. Some of the paj's have a timing advance and most of the gen 2's have it, it's easely recocnized by the 15mm coolant hoses coming from the side of the fuelpump. One goes to the back of the head the other one goes someplace I cant remember. If you don't have it there should be a almost circular lid with three bolt holes on the side of the fuelpump under the throttle assembly. These thing go bad for no reason and can be replaced.

1987 SWB Pajero 2.5 TDI on 31" rubber waiting for a hip replacement and bigger shoes