Okay so I swapped a ls into a friends civic everything is fine car runs great except while under light throttle under 3500 rpms it surges really bad, kinda sounds like a 2 step. I switched out the map with mine same thing although mine is a b16 ( don't know if there is a difference between the 2). Motor revs great all the way to redline under wot. Any suggestions?

 

Well after 3 days of trying to figure it out I fixed it about an hour after making this thread. It ended up being a dirty screen on the iacv.