Hello, My 8 Year Old Cat Throws Up If He

hello, my 8 year old cat throws up if he eats more than a tablespoon of dry food at a time within a few hours. I am concerned that he has a blockage. however when we go away for a weekend we leave him a few bowls of food and he gobbles most of it before we leave with no throwing up. when he throws up you can see the food has expanded 3 fold and there is a lot of it. thank you for any suggestions you may have for me.