I have a 2002 dodge ram 1500 slt with the 360ci and 150k miles. I changed the thermostat and changed the oil and when i staryed it up it would die at idle. Now it stays running at about 650rpms. After revving the engine it stutters and the interior lights dim before resuming idle. What could cause this? Also noticed there is a broken off sensor that connects to the alternator and runs to the motor between a hose and the passenger valve cover. What is this and could it be the issue?

 

Pic of the sensor?

Start with cleaning the the throttle body really well. Pay close attention to the IAC well, as it likes to accumulate junk, and make it difficult for the valve to move.