07 Sebring erratic RPMs
 

My 07 sebring is doing some erratic RPM whenever the RPMs start to decrease.
While accelerating and shifting to an upper gear no problem at all, but then after the speed stabilizes, when going into a hill or on the last gear (mostly 5th gear), the RPMs start to fluctuate rapidly +/- 100 rpms. I need to either release the gas or accelerate to get rid of the problem.
Every time the RPMs are not demanded instead of shifting to a lower gear, this happens.
Could this be a transmission issue or motor related due to a sensor problem?

Possible Fix
 

My 07 2.4 L Sebring would have erratic idle drops at stop signs and in park. This would happen several times a week, some cases several times a day.

It died out once doing this. Would always start right back up. No codes.

Battery was good, I changed spark plugs, PCV valve, and cleaned the throttle body. This didnt resolve the issue.

​​​​​​​I took it into the dealer and they replaced the throttle body and did a PCM update. The problem did not come back and it seems to have fixed the issue.