Child vomiting entire meals, no fever. Had projectile spitups and pyloricstenosis was negative. Suggest?

My 8 month old son has been projectile vomiting entire meals. This happened once two weeks ago, once last week, and three times today. No fever, and he's otherwise quite happy. (I can't begin to describe what a large, large amount of vomit is coming out). When he was 2 months old, he had projectile spitup and was evaluated for pyloric stenosis which was negative, and that resolved. This is out of the blue.

He started on solid foods at 4 months. He generally eats 2-3 solids a day which are a mixture of a fruit, vegetable, and cereal. Grains have been rice, oat, brown rice, and mixed grain. The mixed grain is a newer addition to his diet, but I don't think there's a correlation. He nurses 3x a day and has a formula bottle (enfamil gentlease) 3-4 times a day. This has been the case since he was 6 months (2 months ago).