On my trooper when I took the engine out there was a bolt behind the distributor that I didn't see, all I had to do was remove the coil, and was able to get to it. Not sure if that was any help, but I would give it a good look over to make sure all the blots are removed.
Matt

PICTURES OF MY 1986 ISUZU TROOPER PROJECThttp://www.cardomain.com/ride/2524435/1