My 02 dodge neon has been idling rough for the last couple months and no one can figure it out. It idles rough when at stop lights and signs. The engine really goes irratic when the defrost or ac is switched on to where it will bog out and die. The lights flicker along with the way the car idles. Ive tested the alternator and battery both are good. Wires and plugs changed when i got the car 6 mths ago. I have replaced the iac and throttle position sensor together about 3 mths ago, did no changes, then replaced the pcv valve, no change, i then replaced the pcm with a new one, no changes. I then replaced the cam sensor and it idled good for about 2 weeks with no idle issues but then started surging up in rpms while driving so i then changed the crank sensor and now is back to idling rough at stop signs and lights and gets worse when defrost and ac is turned on. but surging is gone. any suggestions would be great as im at my wits end with this car. Also it does not have any lights on nor is it throwing any codes.

 

have you checked the spark plugs my car was running rough and surging and i changed the spark plugs and that seemed to do the trick not sure if thats your case but its worth a shot in my opinion and not to expensive or time consuming

 

Says they were changed 6 months ago.

 

Our '00 has been havng the same issue,though not every time we drive it (it's...sporadic and random as to when it does it)...we've tried most of what you listed with no difference either. I hope somebody can shed some light on it,for both of us,LOL! (sorry I didn'thave any help to offer,but letting you know,it ain't just yours)

 

thanks for pointing that out i missed it when i read it the first time

 

a friend suggested to try changeing coil pack, since wires and plugs were changed but not that. maybe there is a wire problem somewhere that the last mechanic missed. Maybe it will work, we will see. Id take it to the mechanic but they do not know either. The last mechanic told me it needed a new pcm for $750. the problem didnt change at all with the new one good thing i got a deal. Ive run out of sensors to replace except the vss sensor. I wish it would throw a code off and make it easy but it has to be difficult cuz its a neon.

 

Did it just start idling like that out of the blue, or did you buy it and it was doing it?

 

it started with just a bit of rough idle which was not much to make a fuss over considering rpms would stay at a normal speed, mechanic said it was not anything hed worry about at the time well it progressively got worse.

 

i should tell you that when i bought it the person i bought it from had motor changed at 64,000, there is now 102,000 on it. He had also hit two deer one on each side of front clip. One side(drivers) i had to replace light assembly because it was completely shattered. Ithought maybe it knocked something loose but i nor a mechanic can find it if there is something there. Ive had it completely looked over 2 times for electrical but each time the correct voltage is running through all parts of the car. Thats why the last mechanic said maybe it was the pcm but that didnt correct it either. The problem with the irratic idleing while the defrost or ac runs has always been there but has goten to where if i do run it the car eventually will die while idling. Car runs fine while im driving and it shifts when it is supposed to. It is just the idling that is off.

 

Has the mechanic hooked up a scan tool to read what the engine and sensors are doing while idling?