I posted this in Chrysler forum but it is not to active over there. Anyway have a sebring JXi that at idle and in park the rpm will fluxuate about 200 rpm. The only strange thing is that the speedo will start moving anywhere from 0 to 55 mi an hr. This movement is not irratic. nice and smooth until it levels out fluxuating between 40 to 50 mi an hr. I can then give it a little fuel and it will stop for a minute then returns. Any ideas?

I have not done a thing to it yet. Was thinking I might have a speed sensor or something shorting out.

 

hmmm, if the speed sensor was faulty, you most likely would have a check engine lamp on. If it's not on, I'd suspect a fault in the gauges assembly?