bsflipfrontflip

When i first start the jeep and only when it is cold the car starts up and runs fine. but when i start to drive and i left off the gas and go for the breaks it starts to die but right before it does the rpms kick up to like 3 thousand and than it goes back to normal. Also while this is happening the brakes act like the lines are full of air i have to push the pedal all the way in to get even a little breaking. I assumed it was the fuel filter, changed that but still having problems. Thought i would ask you guys before i would take it in to get serviced.