timing belt question

OK Just replaced my t-belt/water pump (2001 1.8L engine 60,000 miles) and it wasnt too hard - just took some time. timing marks are all lined up and the engine revs smoothly, BUT it idles a little rough. (didn't have a rough idle with old timing belt) seems once it warms up (and the idle revs are a lower rpm than cold start) it gets more rough than when cold. i havent driven the car yet, just let it idle and rev it up for about 20-30 min after the t-belt was replaced to make sure the water pump didnt leak. one thing i didn't do is replace the idler pulley or tensioner pulley/spring. is this necessary to do - replace the idler/tensioner pulleys???? would that contribute to my rough idle?? or do i just need to put some miles on the t-belt to snug it up to the pulleys/gears??

ok - i just replaced the idler & tensioner pulleys and everything is ok and idle is smooth. like a dummy i didn't FULLY tighten the tensioner pulley the first time around. (hence the rough idle) i just released it from the lock position and let the spring tighten the pulley up by itself. i had some instructions from the kia tech website that said not to add additional tension to the tensioner - but i either misunderstood it or it's wrong.... you should tighten it up so that the t-belt deflection is no more than about 1/4" or so between the intake/exhaust gears after you lock the tensioner back up. overall this is a fairly easy job - including the water pump. just labor intensive and will prolly take a person who's fairly mechanically inclined a few hours to half a day.

Thanks for the tip Eck :)