Yea my car does about the same thing bounces up and down from 1-1 1/2to about 2.But when its warmed up it runs fine. I was told the it could be the throttle sensor. The place that did the swap said it could be that the throttle isn't closing all the way. I would've had them fix it but i had to get it out of there for work. They also said that there is a part under the throttle body that might need to be replaced. i wish i knew what the part was so i can explain it better.