99 dodge ram 1500 idle problems
i have a 99 dodge ram 1500 5.9 /360. sometimes i start it up and it idles really low like 200rpm-400rpm then it will cut off. other times i will start it and it will idle like 1000rpm-1400rpm. this is all in park other times i can put it in gear and start going and it will idle up and crusie for a little bit then idle down to where it is supposed to. and thats in all gears. another time it was in park and and just started going from 800rpm to 2000 and jumping up and down for about thirty seconds then it quit. would like for some help or suggestions on what this might be. thanks !!