My idle in park jumps from 1000 and 2200 rpm and some times really rough at idle in park and then it will spontaneously hop. I also think it happens on the highway and it is interfering with shifting etc.Can any one help? It's an 8 cyl 4.7 grand Laredo
Thanks.....

 

Throttle position sensor. It's a black box on the throttle body. Unplug it and see if you idle goes back to normal. If it does, replace.

 

lol even if the TPS is bad, it wouldnt go back to normal if you unplugged it. the engine would surely die.

 

I put in some fuel injector cleaner and it seemed like the cure. Next tank of gas no cleaner then it came back