I have a 96 cobra car that won't idle in cold weather but when It warms up it will hold a rough idle. When I stomp the gas it hesitates and then spits and sputters when I get to 3000 rpm. It has a funny idle but runs fine from 1000 to 3000 rpm. When I hit 3000 it looses all power and struggles to about 4000 rpm then it will jerk u back in your seat. What could the problem be ? Iac? Or miss fire ? I have no clue the code it throws out is number 1 miss fire but I've changed the plugs three times and it dont help. any help would be great! Thanks