Car going lean after startup

I just changed my transmission, converter, and battery. Now when I start the vehicle the afr is about 14.6, when I start to drive my wideband shoots up and reads lean, the car kinda noses over like its lean. It goes lean for a short time, like 5-10 seconds then starts switching normal. It never did this before, the changes were small, went from a 3800 1.69 str converter to a ss4000 yank, tranny is the same and I went to a optima red top battery, could any of these changes cause this? If not were should I start to look? Fuel pressure does not move on the gauge. O2's were new 200 miles ago. Also is this when it goes from open loop to closed loop? I'm a noobie with this tuning so any help would be appreciated, car was previously tuned by speed inc.