lxi problem with idle surge and starting problems

[Beanshonda55]

About 4 months ago i replaced my main rely, because of it never starting after it was ran and warmed up. and after that it was fine and then about a month ago it had idle surges from 1k to 1.5k and then it stopped doing that. then about 3 weeks later i swapped engines with an a20 a1 instead of the a3, everything was running great and every thing and then now it started not starting sometimes, just like it used to. And right when u start my car it will stay at 2 k and then start idle surging from 1k to 1.5k. i just replaced my timing belt to if that helps. could anyody help me out?
Thanks Adam

[LX-incredible]

Was just the block and head swapped? A faulty coolant temperature sensor can make it harder to start when warm. For the surging idle, try cleaning the IACV, that is if you are still using the 89' LX-i intake manifold. Having the idle set too high can also cause a surging idle.