Assuming you are talking about the "out" poppet, i would first ascertain if it is clogging, normally occurs from dry hop residue. If you have lots of that in your keg, either transfer to another keg via jumper set-up, or maybe jury-rig the bottom end of the dip tube with screen or mesh bag (sanitized of course), or saw off 1/4" of the bottom of the beverage dip tub to get above the particulate. Otherwise be sure after transporting to let the keg sit a long time in the upright position (a few hours), so particulate settles to the bottom, below the dip tube, and hopefully it won't suck in more debris as you pour beer.
If you don't think the poppet is clogging, you'll probably be ok releasing keg pressure, remove the poppet(s), and add a bit of keg lube to the o-ring(s), re-sanitize, and then re-tighten, or as mentioned by others put on a spare different poppet from the same brand keg.