Okay my Bronco has developed a little "stumble" whenever I try to accelerate. It isn't real bad but it's driving me nuts. First off let me say it's not the MAP sensor, cat, plugs, wires, or distributor cap and rotor because all have been replaced. So yesterday I was underneath the Bronco when I noticed a hose on the fuel tank wasn't connected. It's the return line, but would this cause the stumble when I accelerate. I haven't run it yet since I hooked it back up.