I gave up wheat and dairy on Friday. On Sunday & Monday ds hardly vomited at all. Monday night I was so starving I ate some wheat and then decided I would give up wheat another time if giving up dairy didn't work. But Tuesday and yesterday ds vomited loads and has been really bad this morning.
The giving up dairy hasn't made any difference so far (apart from I'm starving). Could it have been the no wheat for 2 days that made him better on Sunday?
Dairy is certainly the more common cause of reflux, but I guess it could be possible for wheat to be the problem. My suggestion is that you start eating dairy again and stop eating wheat. You need to do this for at least 2 weeks to really see if it works. To deal with the hunger make sure you have some quick, non-wheat, snacks available (cheesy wotsits or icecream ).
If your DS is still having problems after a few weeks, then try stopping dairy.
His reflux might have nothing to do with food. My DD had silent reflux that was not related to food, although she was also dairy intolerant (grown out of it now).