One problem related to check engine light on has been reported for the 1999 Plymouth Neon. The most recently reported issues are listed below.
Consumer states several months after purchasing the auto the check engine light has been one. The mechanic told consumer that one of the spark plugs were inoperative, which was then replaced, however 5-6 months later the light came back on. Consumer also states when she make a turn the auto feels as thought it is going to shut off. Also when the air condition is on, the auto vibrates.