Chrysler Repair Questions? Ask a Mechanic for Answers ASAP
Before you replace any thing check the signal voltage in the steps I sent you .
Post back if need be and we can work from there.
The code P0303 indicates the computer is seeing an engine misfire on the #3 cylinder, is the engine actually misfiring?
If it running rough at idle then its likely missing on the #3 cylinder, start first with checking to see if you have good spark at the spark plug from the coil and if so check the spark plug.