My automatic-trans doesnt downshift. Especially when at operating temp. I changed the filter and added new atf4 fluid.I have a 5.9l engine, 14 hole transmission. HELP

Also, when the weather is kind of humid when i start up the engine it spits and sputters with no power then it burps and off she goes. I dont know if it is related to the trany problem or what....

you need to retrieve any codes stored in the computer to point us in the right direction.