After getting my 2000 sohc neon about 2 years ago one of the only problems i had was a intermittent lower than norm idle that would happen at stop lights mostly, i could tell it was lower than norm by the feel and the way everything would shake and rattle. I don't think the rpm gauge was accurate enough to read the slight difference, which is why maybe there was never a check engine light. I kept thinking it was the idle air motor, i cleaned it over and over with no luck. Recently i noticed oil on back of the motor, i traced it down in part at least to a cam position sensor that was leaking oil right into the electric plug and it was coming out of the harness. Just on a whim i replaced it and the intermittent low idle problem has disappeared. When a mechanic friend of mine looked at the back of the motor he had said your head gasket is leaking oil as well. I cleaned off the area and i am waiting to see if oil builds back up, i thought they had the head gasket problem fixed on these 2nd gen neons. My car only has 40,000 miles i would like to think that the head gasket would not fail so soon.