My car has been doing this for awhile, so I'm not sure what it is exactly. I've noticed that when I'm sitting still my car's RPM's will jump up and down repeatedly. It also does this if the A/C is turned on. I've changed the spark plugs, wires and battery on it recently and this didn't change anything. Could it be the transmission or maybe even the fuel pump causing this? Help!!
Nope, no check engine codes. That's why I think it's odd.