I had a similar problem with my swap. I received alot of hesitation, very jerky throttle response unless I gave it a load of gas. It ended up being that my TPS - Throttle Position Sensor was faulty (Might also be called TAS - Throttle Angle Sensor) After replacing that, I had very smooth low rpms. Although, I don't see how running hot/cold has anything to do with that. Could also be that you might have your MAP sensor and TPS hooked up backwards. Check your plugs and let us know.
Ugh