Topic: 2000 Chrysler Neon is rough at idle.

[Rilucero]

Hi all,

 I have a 2000 Chrysler Neon with about 107k kms.  For the past two or so months, the car has been running relatively rough at idle to the point where the driver's side door is beginning to rattle a bit.  

 I took the car to the mechanic where an engine tune-up and a fuel injection service was recommended.  I went along with both recommendations (a tune-up was due anyways) but the problem persists.  The tune-up included changing the spark plugs, ignition wire set, PCV valve among other things.  

 Before I take the car into the shop again, does anyone have any ideas as to what the cause of the rough idling could be?  I really thought that the tune-up would at least improve the situation but unfortunately, it hasn't.  Any thoughts would be greatly appreciated.  Thanks!

Regards,

Rafael

[Roadrunner]

Welcome to the forum Rafael.
The Neons are noted to have weak head gaskets. Now, this not to say that is the problem. When the plug wires were installed were any installed incorrectly? Were any of the new spark plugs damaged upon installation?  

Were all the vacuum hoses checked or replaced because they were hard, were loose fitting or had cracks? If so, were there any not re-attached correctly?

Was the air filter changed? Perhaps there is a intake manifold or plenum air leak?

Dirty fuel, a faulty fuel pump and or a dirty fuel fiter or poor fuel pressure in the fuel rail and/or dirty fuel injectors can contribute to rough running and the list goes on.  

I'm sure other regulars on here will contribute their expertise on the subject too. Please stand by.

[Roadrunner]

OOPS! I see there was a fuel-injection service just done. Can you tell us what they did?

[Rilucero]

Thanks for the quick reply.  The fuel injection service had the following description:

"Clean carbon and varnish deposits from fuel injectors, fuel rail, combustion chamber, intake manifold and throttle body as required."

The tune-up had the following:

"Install listed ignition components and filters, scope test as required and adjust to factory specifications.  Check all underhood fluid levels and clean battery terminals."

The mechanic also mentioned to me that the engine mounts were checked, and that they were in fine shape.   I've recently noticed that when the engine is idling, I can sometimes hear a faint but persistant squeaking sound coming from the engine.    

Hope this helps a bit and if you need any more information, please let me know.  Thanks again!

Rafael

[Barrie1]

I would try to get a Diagram of your engine and Definitely check your Small Hoses for leaks. It only takes one small leak to make Nasty things Happen.  

[johngenx]

Don't take it back to that mechanic.  He/she didn't correctly diagnose the problem prior to installing new parts.  And I doubt they'll be able to find the problem without a huge investment of your money in labour and more parts.

There are many things that will make an engine rough at idle.  Vacuum leaks and air intake leaks post-sensor are some typical culprits.  As the condition is getting worse, it's something that is breaking, not broken.

The list of potential suspects is long, and if you just keep throwing parts at it, you'll probably get it eventually, and you'll also be very broke.

[Rilucero]

So would you recommend just waiting until whatever is breaking eventually breaks so that the problem becomes obvious?  Or would you recommend taking the car to a different mechanic in the hope that they will be able to correctly diagnose the problem?  Considering that the problem could be a wide range of things, is it likely that any mechanic, no matter how good, will be able to track it down without costing me an arm an a leg in labour?

 

[johngenx]

I have a friend that is a BMW/Mercedes mechanic.  He spends his days working on the most complex cars made, period.  He NEVER throws parts at a problem, and always has an accurate diagnosis, no matter the problem.  Some are indeed tough to solve, but the idea that you just keep throwing parts on the car until it's fixed is just plain wrong, and it shows a lazy attitude towards problem solving.

Finding a mechanic that will do this can be a trick.  You can ask friends and start calling around to find out if a shop can give you some info on how they'd go about tackling your problem.

There are fundamentals that need to be checked.  Why were the plug wires replaced?  Were they not functioning properly, or was this part of the "fix?"  If they were fine, then you wasted money replacing them.  Plug wires can be checked, and don't have to be replaced to find whether they are good or not.  Of course, you should be charged for the labour of checking the wires, but why pay for the replacement of good parts?

Take Air Mass Meters, as an example.  This is a common failure part on many OBD-II cars.  My friend knows that when reading the OBD-II codes, along with the adaptation values, he can be 95% certain that the AAM is faulty.  Then, he uses a known functioning unit on the car, rechecks adaptation values, and if it works, he puts a new AAM on.  If not, the old (working AAM) is replaced and he moves on to the next thing that can cause rich-running max adaptation values.  Many mechanics just read the codes and then slap a new AAM on, and charge you a whack of cash for the new part.  Well, if it's not the AAM, and you come back, tough luck.  Then they throw more parts at it.

Take the cleaning of the EFI system.  Was it showing low pressure?  Is there a lean burn condition making them think that the fuel flow is impeded?  Or is it just a high margin job that they beat everyone over the head with?

Perhaps your mechanic just did the "tune" as you asked, and didn't really work on the rough idle problem.  Perhaps a chat about the specific problem is in order.  If he has no idea other than to begin throwing more parts at the problem, then your next task is to work on finding a new mechanic.

[Roadrunner]

Rafael
Finding the cause of the rough idle will take time. Hopefully the time is not at $65-$70 an hour. I agree with the guys, try to find an independent (or two) who can narrow down the probable cause, including giving you the same answer.

The squeeking noise can be anything from a pulley bearing to a loose/glazed belt. Possibly even a deteriorated donut gasket at the joint of the exhaust manifold and the exhaust pipe. (the bolts rust and the joint becomes loose)

Don't resort to band-aid fixes. That's lost money.

[Sadie]

All everyone - I have a 2000 Chrysler Cirrus,2.4 L engine that has a rough idle - have replaced spark
plugs, ignition wires, clean injectors, replaced
PCV value - no one at Chrysler service seems to be able to help with the problem . Any ideas as to what
I can try to get rid of the rough idle ? Thanks
Sadie

[Roadrunner]

Sadie, welcome to the forum. Sechelt eh? I'll be darned.
I see by your post you have gone the way of the rebuilder too. With no good results.

First and foremost, go find a trustworthy and reliable independent repair shop. Word of mouth will steer you in the right direction.
The best way (I think) is to put the car on a diagnostic machine. We can sit here and play guessing games all night and not come up with the correct solution.  

Although you have had 4 of the usual culprits changed to no avail suggests something not quite so obvious. More suggestions (unless positive) will have you spending more lost money.

Re-read Johngenx last paragraph.

[Derweissehai]

Hello Group,

I have 2000 Plymouth Neon. I was looking into taking off the Govenor for the engine and need to know if it will mess anything up and also where is it located. Is it on the engine itself or is it computer controlled. Thanks in advance.

Adam