Rough idle at startup

When starting the truck, it sometimes idles real bad, almost like it'll stall or something. After about 5 seconds though it goes back to normal, drives fine afterwards. Have changed the fuel injectors before due to them clogging from debris and often smell gas from the engine area. Also swapped the throttle and a lot of sensors. No idea why it idles bad though. Also, strangely this doesn't happen in the winter or temperatures below freezing.