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Discussion Starter #1 (Edited)
I have an '06 Sorento V6 with 108,000 miles. Over the last few months it has developled a slightly rough idle when sitting in park. I decided it was time to change the plugs and did so using NGK Iridium plugs. The rough idle backed down just a little, but seemed to come back and even a little worse. I had to remove the throttle body to get to the passenger side plugs and I am afraid I may have tweaked something when unbolting it and setting it on top of the engine.

Today I took it to Valvoline for an oil change and decided to get the fuel system treatment done to see if that might knock some of the cobwebs out and smooth out the idle. Upon leaving from there, the check engine light came on and I took it to O'Reilly to have the codes read. I got p0300, p0304 and p0306.

I immediately went back to Valvoline and they told me that this was normal after getting the fuel treatment done. They cleared the codes and told me to come back if the light came on again. While sitting in the store parking lot, I noticed the idle bumped up from around 850 to 1000 and the idle smoothed out.

For the next few hours, the idle seemed to fluctuate between 850 and 1200. I noticed when driving when I would take my foot off the gas the rpms would drop by a few hundred for a split second and then come back up. Now the idle problem is back and the check engine light is back on.

I have a few questions, could the fuel treatment have done something to foul the new plugs I put in? Would a failing Idle Control Motor/Valve cause the codes I got? What would be the first logical thing to check before I start buying parts?

I should also add that when driving on backroads or the interstate the vehicle runs great!

Thanks
 

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Sounds like you have a dirty IAC (intake air control) valve. It controls a disk (butterfly) that opens and closes to control the amount of air the engine receives at idle. If you follow the large black "hose" to the aluminum tube (throttle body) and remove it there...When you look into the throttle body you will see the disk and the throat (inside walls) are covered in a black coating that restricts free movement of the disk (causing idle problems)... Some "choke and carburator cleaner" (available at Advance or AutoZone) sprayed into the throat and onto the disk and lightly scrubbed with an old toothbrush and an old cotton rag (tshirt) will remove the "gunk".
The other problem (P300,304,306) may be caused by bad plug wires and/or wrong spark plug gap settings... I believe that yours should be set at .044" and pregapped plugs are not always "gapped" correctly from the factory...
Spark plug coils are also known to go bad with time...

Lots of variables out there and you could throw money at the repairs..You need a scanning reader to "look" at the data coming from the engine to actually find the one problem..
Dave
 

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Discussion Starter #3
Thanks Dave, I think I have fixed the issue. When I took the throttle body off I did not put the gasket back on in the right orientation. I fixed that and cleared the code. So far so good.
 

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2007 sorento Global Curcuit
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could this be the same problem on my 2007 Global 3,8? At random times the motor will go into protection mode and have a rough idle. I have to turn motor off wait 10 seconds and then she is fine. this could happen at any time.
 
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