I'm the one who had the weird misfire that someone linked above. Funny but my #2 spark plug was bad and that's all it took to fix it. But mine had codes for 1 and 2 which is what made it so weird. Anyway, I wouldn't fret about the non iridium plugs. Toyota calls for standard plugs on our vehicles. My understanding is the only benefit to iridium or platinum is longevity. So they stick them in any vehicle that requires extensive labor to replace them. And as you've probably figured out by now the plugs in ours are fairly simple to replace. Glad you got yours fixed. Oh, and about that low idle. If you've had the battery unhooked the idle will be low for a little while until it relearns where it needs to be. If you haven't had it unhooked I'd suggest cleaning the throttle chamber and plate. That will pick it right back up to where it should be. Good luck.