I can tell you my experience. I had the problem with my 2000 Dodge Dakota V8 4wd quad cab almost from day one. While sitting in idle, the engine would race, whether in park, at a stop light or behind someone in a line and yes even driving down the highway with cruise control on. I took it to several dealers and was told by all that they could find nothing wrong, but they all charged plenty to run the codes and diagnostics. A couple months ago was the real kicker! I was at a stop light and behind another car and it decided to race, ramming the car ahead of me not once, twice but 3 times and all while my foot was on the brake! (There simply wasn't enough time to throw the gear into idle). A friend of mine recommended I take it to yet another dealer because they were honest! I took it there and in no time, they found it to be the throttle sensor. And although I had just had the fuel injectors cleaned by a quick lube place, they said to check and see if they actually cleaned them out or just flushed them. (They had just flushed them) and the mechanic said they needed cleaned thoroughly. Between these two things, i have a truck now that runs BETTER THAN NEW! Unfortunately, I received a ticket for failure to reduce speed to avoid an accident, even though I was stopped at the time! I hope my expensive lessons work out for you!
