2009 SEL idling rough - spark plugs questions+

[crsuribe]

Hi,

Been reading this forum all day and have found lots of great information.

Like the title says my 2009 (70k mi) is idling kinda low and rough and it seems like new spark plugs would really help... Ive been looking at the motorcraft copper ones but cant find them locally and dont wanna have to wait for shipping so figured id just get the platinum motorcrafts... Any opinions?

Now my other main question is: i wanted to change the plug wires but i called vato zone and they said my car takes coils not wires and that they are $97 each for the motorcraft ones. Id read that its important to change the wires for better performance but this really shocked me. Can someone help me understand more about this?

I also want to change the air filter; any suggestions for a good brand that is easy to find?


Thank you very much for your help, guys. This is my first decent car and I want it running smooth and taken care of!

[Sponsor]

[Urbanspacedude91]

Ok first off welcome to the forum. =)

Lets get started. So the copper spark plugs are good but for our focuses they are used because they are a step colder for vehicles with turbos and or superchargers. If your vehicle is stock then what you bought is good enough.

The filter should be a "lifetime" filter. Most guys just get a new aftermarket intake system as far as replacing those i usually do that when i notice its extremely dirty. But if no aftermarket intake system you shouldnt buy a filter unless your gutt feeling is telling you too. Its never nothing wrong with taking extra care of your car.

Its no reason to change the coil on plug wires only the sparkplugs inside of them. Thats just the store trying to get you to buy stuff. There is a performance option for the coil wires on cfm website which i think adds like 4 hp. But for 250 would you buy those??
This is just from my experience.

[crsuribe]

Thank you for the information! Is there a specific method for gaping the spark plugs if they're not correctly pre-gapped?

[Urbanspacedude91]

If not you would need to know the specs from ford and there is a tool you can use to measure the gap as your screwing it in. Not sure of the name

[whynotthinkwhynot]

08-11 Focis should have a replaceable filter. Check your owner's manual for more information, but the air cleaner box is behind the driver's headlight in the car. 05-07 Focis and the early PZEV were the ones with the lifetime air filter.

COP ignition does have replaceable parts. To remove the coil, remove the bolt, then rotate the coil to break the boot loose, and pull up. When you remove the coils to get to the spark plugs, you'll see a boot on the bottom of the coil that connects it to the plug. That boot does go bad and can be replaced- cost is $5-8 each. Mine went bad around 80k miles. If you have a leaky valve cover that gets oil on the boots, then when you repair the valve cover you will want to replace the boots.

There are multiple tools to check gap. Gap on these engines should be listed on the VECI label under the hood, and IIRC is .052". Just ask the people at the parts store about a gap tool. The simplest gap tool to use is the round coin style. There is a hole in those that is used to adjust the backstrap (or electrode). You simply put the tool in the gap, and rotate it around. When you can feel the tool lightly scraping both sides at the same time- then you have reached the proper gap.

On Ford's platinum plugs, the tip is so tiny that adjusting using this method might damage the plug center conductor or anode. I have never found Motorcraft plugs to not be pre-gapped. I often tell people never to trust pre-gapped plugs, but that's for standard plugs. There are edge fire plugs and some fine tip platinum plugs that you can trust. I generally check, but you have to be careful when checking so you don't damage the plugs.

[whynotthinkwhynot]

Wait.... PZEV versions of 08-11 Focis might have a lifetime air filter. You shouldn't have a PZEV in Ohio, but it is possible. Your owner's manual will have more information than I can give you without a picture of your engine compartment.