Yeah, the weird thing with my BX when it does that, is that removing the cap won't 'fix' it. But disconnecting the fuel line from the electric fuel pump, turning on the ignition and making sure the pump works (it'll be pumping out fuel onto the ground). Then hooking the line back up and the tractor acts like nothing is wrong (bran new tractor). If yours has any age on it, I would pull the fuel line first to make sure the lift/electric pump is working. If it is working and pumping fuel out with the ignition on, then maybe putting the line back on will 'fix' the issue like it does with mine. Like I said, I'm fairly convinced it's a tank vent issue. For some reason, it once the problem gets started, it won't 'self correct' with simply taking off the fuel cap. Unfortunately for troubleshooting purposes, I don't run through a tank of fuel every week so that I could verify what's causing this. But cleaning out the tank cap vent definitely kept the tractor from doing that sputtering/stalling thing for a while until it got iced up again (Alaska, so........)