Rio with rough idle

[Sabasfan_08]

I have a '08 Kia Rio, 5spd, base model. When sitting and idling I notice the idle is rough sometimes when coming to a stop it feels like it wants to die, but it doesn't. I have recently just replaced the plugs. They are NGK stock plugs, pregapped and still it idles rough. I was thinking it might be the coil packs, or fuel filter(s)? Maybe even the injector? Where are the fuel filters located? I know there is supposed to be one in the tank? Is there one up front and how hard are they to change? Also the coil packs can I order them from a parts store or do I have to go to the dealer? I prefer not too since our dealership here rips people off. I have not taken it to see if shows any codes. I believe Autozone does this? How much do they charge or is it free? Also I have considered running Seafoam. How do I run it straight through my engine. I know you use a vacuum line but where that part I'm not very familiar with? Any help would be great. I am mechanically inclined to some point I try to do as much as the maintenance myself as I can. If anyone can give me any advice it would be greatly appreciated.

[RecoilRob]

When it 'feels like it wants to die', how fast is it running? Slowing down when coming to a stop, the fuel injection is actually shut off most of the time. Just before you stop, it turns back on to keep the engine running. You might be feeling this if you are slowing down in gear with clutch out.

If in neutral or clutch in....I'm not knowing for sure as it should be idling although some will idle a bit higher until you actually stop. Being a 4 cylinder engine, it is normal to feel it shake a bit at low rpm...especially if you have some miles on it. The engine mounts tend to get firmer as they get older so you feel more shaking with old mounts than new ones. This is assuming that the mounts are all in good shape and you don't have a broken one...which can cause some shaking for sure.

Fuel filter is in the tank...don't worry about it. I'm not super happy with the stock spark plugs they put in the engine. Mine didn't run good at all until I put better plugs in it.

How is the gas mileage? That is the best way to determine if the engine is healthy or not. If your mileage is normal, and the engine runs well except for the shake at idle, look at mounts or something external for the cause.

[rkkeller]

Have you changed the oil recently?