hi.i have a 97 chev 1500 with a 6.5 turbo diesel.it has been sitting for about 3 years and i have decided to get it running again.the truck starts fine but has a very erattic throttle.it idles around 5000 rpm till you press accerator,then it jumps to 11000 rpm.it sits at that and again may jump to 25000 rpm.the only way it will come back to 5000 if you put it in gear.ive seen posts on this problem but i never see a solution.any help would be appreciated.i dont mind putting a ip in if it will fix it.