I'm thinking that you need to give it a bit more time. At an hour and a half a pound a 2.5 pound loin should take atleast 3.75 hours. This is just a guide line though. It could take longer. I've seen cooking time go as much as 2 hours a pound. Time and paitents is the formula.
you may be hitting the plateau but if ya got good color on it & it's had smoke the whole time-or you just need to eat today,you can wrap in foil (or tent) & oven finish @ 200-225 for an hour.be sure to let it rest for a while before pulling if your pulling it or just to be tender.
Dee, I just finished up dinner 3 hours later than usual. It was worth the wait though. Wow that was good. I used a recipe from your site. I rubbed the loin, then rubbed applesauce and let it sit over night. I poured apple juice into the pan and threw in a cut up apple into the pan. I am not sure I quite have the right idea on getting that smoke off of the electric ECB.