1991 Trooper

Hello. I recently picked up a 1991 Trooper for a heck of a price because of no title or registration. I finally got that little chore taken care of. This Trooper has the 2.6 and 5sp transmission. It has 171k on it and it does need a tune up. I used to own a ’87 Trooper, so I am familiar with first generation Troopers in general, but clueless when it comes to the Itec 2.6. Anyway, when I start it up, it will sort of sputter for a second or 2 and then idle at 1500 – 1700 rpm and won’t drop back down. My questions are, where is the idle adjustment located, and does anyone have a vacuum hose diagram? I am thinking that after I change the plugs, wires, cap, etc it will probably still idle high. What will I need to look for? My next question is that the fuel gauge and temp gauge do not work either. I understand that there is a gound cluster somewhere around the rear crossmember that affects the fuel and temp gauges? Where exactly is this located and what am I looking for?
Thanks for any information.
Jim Welsh