First off i have 91 crx si, a couple weeks ago my timing belt went and as a end result my mechanic told me i had bent valves(he checked each cylinder) . My car was running weak and i got all the parts together for him to do the work but then after a while my car began to work as it did before. My idle before my belt went was at about 1000 rps but now every once and a while it dips below that by a tiny bit, i can feel the engine struggle a little bit just like when you turn on your ac. I took my car to a friend of mines who is also a mechanic and we tested each cylinder and they all were good. He told me i just needed a new distributor and a tune up. What do you guys think? What could be my problem, my car runs good as new most of the time but sometimes the idles off and it just doesnt feel the same.

Also is there a way to set my cars idle? Could i raise it? Will i waste more gas?