Xterra TIming/idle adjustment

[xterrible]

Ok, so i replaced the timing belt, and the the engine runs. I got it all put back together and I gave it a good test drive. first off, i think my belt tension is too tight, so i am going to have to adjust a few of the belts, no big deal. But, around 2500-2800rpm the thing just takes off. then it idles just above 500rpm, very rough...and it is making a weird noise that maybe one could say is a ping. I went up a very large hill near my house and i had a little loss of power. drove it along a moutain road by my house and I notice very little power at 200rpm. I think my timing may be way off, and it never idled just above 500 rpm before the belt went. I also did the distributor, plugs, rotor, wires...i tried to touch all the bases when i had it all apart in my barn. You think i should adjust/check the timing...adjust the idle?