[sugarbuggy]

Hi!

I have been a lurker for years, but a new member today. I drive a 2004.5 Kia Spectra Ex 2.0L... 144K. Have been trying to fix a rough idle for a few months now... each time I get it fixed, the symptoms return or worsen.

Presently, the idle speed jumps up and down when in drive while coasting or stopping. Will stall 50% of the time at a stop. Must throttle to re-start.

Idle speed in Neutral varies: when hot it drops below 500rpms. When cold neutral idle is high... like 2000-2300 rpms. **If I run the A/C while in Neutral or Parked the idle speed temporarily returns to normal**

Idle speed in park drops and often stalls when hot, when cold it is normal to high range.


OBD Codes P0140, P0172, P1166... Diagnostic at a local shop reccommended a tune up, replace both O2 sensors, and purge valve.

Last time I had the car repaired, EVAP canister solenoid was removed and inspected and re-installed. Afterward the kia would then idle great, but would stall once you pushed the throttle. I was told to replace PCM.

Instead I took it to another tech, who inspected electrical system and sensors. He got the kia going again: no error codes, no issues afterward for about 2 months.

Now the problem is back with a bite. Stalls more often, harder to start when hot, and loss of overall power. Recently tested battery, alternator, and starter... all fine. Replaced the battery terminal connections with brass fittings. B12 Chemtool fuel treatment.

Before proceeding, can any of you veterans offer some tidbits of wisdom regarding this issue? The repair estimates are stacking up to over half the value of my vehicle. Ouch.

 

[DavesSpectra]

Codes sometimes do not point to the "exact" problem(s)
P0140...Bad secondary O2 sensor (no activity from sensor)
P0172....Possibly a bad fuel injector (too rich) and possibly sputtering at low idle.
P1166...MANUFACTURER CONTROLLED FUEL & AIR METERING problems

I would have the second O2 sensor readings checked in real time, It sounds like the sensor is not functional (P0140) and is one problem. Real time OBDII sensors/programs will help in diagnosing by graphing the voltage coming off the sensor.
A bad O2 sensor can also cause failure of the secondary catalytic converter by adjusting the air/fuel incorrectly.

Have the engine temperature sensor also checked cold and hot. (OBDII reader)

You may have problems with the IAC (Idle air control) valve located in large aluminum "tube" causing rough idle, speed variations, and stalling.. This is a problem becoming more common in higher mileage Spectra/Sportage/Rios. Usually a good cleaning with carburetor/choke cleaner and a flux/toothbrush on the butterfly valve and inner surfaces... Be careful of the "toothbrush" option as a cleaning tool as the cleaner may attack the plastic in some.

Another sensor that causes problems is the MAF (Mass Air Flow) sensor located in the large rubber air hose. It is very fragile and should not be touched.. They make an aerosol cleaner made just for that purpose. A bad (dirty) MAF will also cause idle/RPM/stalling.

This guy "OBD Codes P0140, P0172, P1166... Diagnostic at a local shop recommended a tune up, replace both O2 sensors, and purge valve." looks more likely the best one to do business with... I'd start with replacing the secondary O2 sensor, cleaning the IAC
valve, and cleaning the MAF.....and go from there...

Do NOT replace the ECM...They seldomly fail and a waste of your money.

Dave

 

[DavesSpectra]

BTW...
The spark plugs and wires should also be replaced with this amount of miles (144k).
If nothing else it has to improve performance.
Dave

 

[sugarbuggy]

How did I know it would be dave to the rescue? In fact... when one mechanic suggested pcm I told him to get lost just based on your past expertise.

I went ahead and scheduled to change the spark plugs (NGK iridium) and to clean up the IAC/throttle body. I'll add a proper MAF cleaning to the list.

My concern is this: electrician 3 months ago tested and gave the ok to the sensors. In fact, the only sensor he mentioned was the cam sensor because I had 12v reading on both ends. I assume that this was what he repaired.

I am always weary of the O2 sensor replacement because in my past with other makes/models of cars, shortly after replacing those sensors a domino of issues would follow.

 

[sugarbuggy]

Oh, and the tech who reccommended a tune up and senor replacements did his diagnostic with the real time OBDII program. Told me downstream o2 was dead and upstream was not working very well. no Mention of temperature sensor.

 

[DavesSpectra]

I'd believe him...They do go bad around 120k on most cars...I like he used the correct tools for diagnosis and didn't "throw" parts at the repair..

Your mechanic probably moved some wires and "corrected" temporarily the problem.
If you re-check the cam sensor and get 12v on both ends of the connectors...I do believe they normally have one end going to ground (0volts) and if you have 12v on both you have a bad ground connection. This might be your "problem"... a corroded or intermittent ground. Look for (usually) a black wire bolted to the engine/frame/body and remove clean under it and add silicon grease to keep the water/salt/air out.
Keep us posted as it helps others in the future...
Dave

 

[DavesSpectra]

btw...
Not replacing bad/worn out O2 sensors can cause the air/fuel mixture to go rich and KILL your Cats and throw off your gas mileage to boot... I've heard comments on using "after market" O2 sensors causing problems BUT if you use a brand name like "Bosch" spec'd to your car you should be OK. Most O2 sensors have voltage outputs in the range of the originals during normal operation.
Dave

 

[windtwirler]

clean or replace butterfly valve in throttle body. rebuild throttle body.

 

[DavesSpectra]

windtwirler...
Look at the date of this thread....It's nearly a year old...
Newbies take time to "learn" the forum
Dave

 

[kimmeastar]

Dude, I am having the EXACT same problem. I have a 2004 spectra 2,o also, have the same codes. I'm in the process of changing out my #2 O2 sensor. Will post here the results. Did you ever fix yours yet?

 

[kimmeastar]

OK, I just swapped out 02 Sensor number two, and everything seems to be running okay and a LOT better. I'll be doing some driving later, so I think that will be the true test. I'll update you later today or tonight.
Here are some of the other things I also did.
1. New wires
2. New plugs
3. New idle control motor
4. New o2 sensor #1 ( I had a code for this previously)
5. New throttle body
6. Cleaned MAF sensor and screen (it was filthy)
7. Cleaned out air intake scoop (filthy)
8. Removed and cleaned fuel injectors, installed new rubber seals on them

Today, I also disconnected the negative battery cable, as I always do when performing maintenance, but also to let the computer reset with the new sensor installed. My mileage is 189,624 and it still runs like a champ. As long as it keeps going good, I'm going to keep driving it.

 

[kimmeastar]

OK, car ran better, but the problem with the rpm fluctuating up and down was still there. The last thing, and only thing left was the ignition coil. I changed that today, and bingo! Idle rpm normal, no fluctuation, and the check engine light even went off. So, with all the bad parts I had to replace, my engine is running like it just came off the sales lot! I am at 189,000 miles, and I should get even more with regular maintenance. Good luck to you all.

 

[DavesSpectra]

Well if the coil pack had a high voltage leak that could cause a poor idle and misfiring..
Glad you found the root cause of your problems...
Dave