What could be causing this

My boy gunner has had this lip smacking and gulping going on for months. It comes and goes. Some days are worse than others. Saw vet about 3 months ago for this and he suggested putting him on Pepcid ac twice a day. It seemed to work okay but he still had very small episodes. Yesterday and last night were awful. He started yesterday afternoon with the lip smacking and threw up his meal. We gave him some nausea medicine (cerenia) the vet also prescribed in case he had another bad episode. That doesn’t seem to be helping, it’s the first time we had to give it to him. Taking him to vet this morning as soon as they open up. is there anything else I could suggest or anything someone might have information on I can give vet? He did mention getting a scope done if this persists. Could it be anything other than the acid reflux he is being treated for. Digestive?internal organs? His gums looked good last the last vet visit 3 months ago. Thanks for any information.