With your mileage fuel filter and plugs should be changed. Regardless of idle problem, I don't know if there is any connection between the two.

Plugs are easy, and fuel filter is easy.

For around twenty bucks, you can buy the euro Haynes manual and it has tips on how to do the work.

You should check the archives on this forum for doing the work, there are many little tricks to perform a smooth job.

I've done both jobs- fuel filter within the past two months and plugs a little over a year ago.

For plugs, you remove air intake and coil/plug cover. Mark or remember which leads go to which plugs. High tension leads screw away from each plug hole. Use care when removing wires from plugs, pull on head of leads and not narrow wires.
Use OEM plugs- I think they are pre-gapped. There is a trick of using a proper sized hose connected to top of spark plug in order to screw in plugs so you don't cross thread them. Finally plugs can be torqued. Using anti-sieze on plug threads is something you can research on this forum.

Fuel filter replacement can also be researched on this forum. a couple of tips.
Purchase OEM filter - have your vehicle VIN number handy when ordering filter - also get new fuel filter clamps.

You need two hose clamps that squeeze line tight so gas won't spill, These clamps don't need lots of pressure to squeeze hoses tight and they should be rounded so they don't stress hoses.
The factory hose clamps that tighten hoses to filter (different from clamps to cut off gas flow) need to be clipped off, they may disengage with a special tool, but I am not familiar with it. The new hose to filter clamps are simple screw tighening clamps.

Hoses take some heavy twisting to remove from filter, just pulling with bare hands may not work. A bit of prying with heavy duty rubber gloves may be needed.

Also you will need some socket extensions in order to unscrew bolts that hold fuel filter cover to car chassis.

Disconnect battery before starting fuel filter replacement, and be aware of sparks. And yes, filter is located passeneger side rear in line with rear diff.