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Discussion Starter #1
Hey guys, I have an older Santa Fe 2006 3.5L V6 (160K). Purchased new car and kept the Santa Fe as a second vehicle. Was running great but got busy and left it in garage for a couple months. Started it up one day and it has poor idle and trouble code P0305.

Odd, as it was running great prior to this and considering its on the same spark plugs from factory I thought I'd change them and the three plug wires while I was in there.

Not a quick fix on the V6 model but I got the job done. Plugs looked old but nothing stood out other than a larger that optimal spark gap. Started it up and had the same P0305 error.

Cleared the code and swapped out the coil attached to cylinder 5 with adjacent one, as they are up front and super easy to access, to see if it was a bad coil. No dice. Same P0305 error.

So I'm thinking its a faulty fuel injector as this is the only cylinder that's having issues. Fuel pressure wouldn't affect just one cylinder, it couldn't of developed compression issues in two months of sitting idle. Id suspect a bad O2 sensor would give bad readings to the computer and affect all the cylinders not just one.

Any thoughts? Could sitting idle foul an injector?
 

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Logical conclusions. Have a listen to the injector with a screwdriver against your ear and compare it against the others that you can get to. Is it possible to swap the injectors over? If not try a bottle of injector cleaner. I had a similar problem with an older car and it wouldn't idle and ran like a dog after sitting a time. The cleaner fixed it within a few days. No a believer of snake oil but it did work. Another thought is a possible manifold air leak. If you have a vacuum gauge it should have around 20 inches at idle if all is well.
 

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Discussion Starter #5
only swapped the coil. If it was a bad coil the error code would of changed to a new cylinder.


You swapped the ignition coil, but what about the HT lead (the wire) that connects the coil to the effected cylinder? Did you swap that too?
 

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Discussion Starter #6
On the V6 the plenum covers the firewall side 3 cylinders. If you want to change the spark plugs on the cylinders you have to remove the upper intake manifold. So you might as well change the 3 wires back there as well.

V6 and 3 plug wires?
 

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only swapped the coil. If it was a bad coil the error code would of changed to a new cylinder.
Yeah, but if the HT lead (the wire) was bad you'd still get a cyl 5 misfire regardless of what coil you connect the lead to.
Or did you swap a coil complete with the lead attached?

V6 and 3 plug wires?
The front 3 cyls are COP and there are HT leads that connect the coils to the rear cyls.
 

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Discussion Starter #8
Yeah, but if the HT lead (the wire) was bad you'd still get a cyl 5 misfire regardless of what coil you connect the lead to.
Or did you swap a coil complete with the lead attached?


The front 3 cyls are COP and there are HT leads that connect the coils to the rear cyls.
I replaced those spark plug wires for new ones. For the coil all you can do is move the coil to a new location and leave the wires in the same positions, otherwise you'll change the firing order.
 

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Discussion Starter #9
Sorry guys, I think my orginal post was not descriptive enough, but posting to a specific "Santa Fe" forum I was hoping for someone who owned a Santa Fe. I do appreciate the suggestions/advice.
 
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