"sticky' at the top will give a full rundown on the "test mode" for the odometer.
Given the model year, I'm SURE there are enough miles on the car - and FOR SURE enough years to need a timing belt as a basic maint. preventative measure. Unless yo check it and it looks BRAND NEW start saving for a belt, tensioner & idler pulley (avail. as a kit), and to save doing things twice many recommend the full maint. on serpentine (belt, tensioner, idler pulley) & even water pump as well.
None of this is urgent, unless something looks bad right now - it's just needed to avoid future issues when you can get around to it.
Fuel filter IS an important piece to make SURE it's been replaced recently, since MANY issues result from one that's gone too long without replacement.
Factory plugs, with the gap checked, give the best results for a daily driver both in operation & longevity. Wrong gap in particular, and non-stock brands, sometimes cause issues as noted in practical experience from many posters on this site.
The IAC isn't a "line", it's an electrically controlled valve that looks like a cylinder attached to the throttle body. Search long enough & you'll find a picture somewhere here - sorry I can't give a direct reference to the posting for that...
Did you check the old plugs for condition when removed? THAT is the best diagnostic for engine running condition over time... Deposits, color, all important! There are many resources with pictures for spark plug condition diagnostics, both on-line & in printed manuals. A glance at a diagnostic chart for plugs will teach you a LOT about what's going on in the engine...
Keep checking, get back with more info. & all the regulars here will help you work through any & all issues!
Luck!
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