I have a 87 Pathfinder. Have had it about a year and love it. the person I bought it from abused it badly. The Engine and tranny run strong except for one problem that I can't figure out. When I warm it up after about a min the RPM will jump between 1500 and 2000 every couple seconds for about another min then it will level off at 2000 and go down slowly till it is about 1000 and completely warmed up. Sometimes it will do the same pulse thing when I get to work and let it idle in park for a little bit. I don't play in the mud or anything with it. about the only time I use the 4wd is when I need to pull someone out of a jam or it is snowy. Will be switching to manual hubs sooner or later. Also the person that I bought it from somehow snapped off the passanger front lower shock mount. How hard would it be to replace it. I am guessing I would have to replace the control arm?