go to this website www.planetisuzoo.com and slowly scroll down to Isuzu Torsion bar adjustment that is where you should find your answer to this question.
How do you adjust the valves on a 1995 isuzu Rodeo 3.2
how do you adjust head ligths up or down on a 2001 Isuzu rodeo
adjusting Isuzu rodeo brakes
16mm street
there are no adjustment less you have air shock
diagram of rpm in trooper
The timing is not adjusable It is distributorless ignition
replace the hydraulic tappets in the rocker arms, valves are non adjustable.
http://www.onlinefreeebooks.net/automotive-machinery-power-equipment-ebooks/isuzu/isuzu-n-series-isuzu-elf-workshop-manual-pdf.html see page 57 of the manual, basically you are putting the no 1 and no 4 cylinders at top dead center and inserting an .016 feeler gauge.
Check the Isuzu owner's manual for informational on the rear brake adjustment procedure. If the manual is not available to you, your local library may carry or you can seek advice from a certified auto mechanic.
Put engine restore in it, it will also help if your valves are tapping.Its in a silver blue and red can its about $8.
It has 2 adjustment screws, one controls the angle in/out and the other controls angling up/down.