hard to start rough idle

ok so i just bought a 1999 Plymouth neon 125,000 miles not sure if engine is DOHC or SOHC. So it has this little problem where it starts hard (cracks and spudders for awhile till it starts) then it is like a jittery idle even when warm but drives just fine not even a tiny miss. then when you come to a stop it gets rough again. the CES light is on but i dont have the car here yet. when i get it i can pull some codes but im just looking to see ideas of what may be wrong with it. Thanks Mike

alright got the car here. its a SOHC and the codes are:
12
54
55

12 - nothing to worry about
54 - Camshaft sensor
55 - End of codes


So it needs a new camshaft sensor right? Would a bad camshaft sensor cause poor throttle response also? cause in park if you hit the gas it takes a second to rev up.

ok i changed the Camshaft position sensor and it starts better no CEL but still spudders while idleing. any ideas anyone? Maybe bad gas i think this car sat for awhile. (30 days or so)

change pugs. that may do it