I am making braised short ribs and used red wine that had turned vinegary by mistake. anyway to fix this? It's in the oven now for 2 hrs

The flavor will probably be just fine. No doubt it's too late for this idea, but you could also remove half or so of the braising liquid and replace with a similar amount of chicken stock, beef stock or diluted bouillon.

I'm sure there's a lot of great flavor in the liquid you have, though, so you really don't want to waste that by essentially starting over with all new liquid.

Honestly there are a lot of braised short rib recipes that call for vinegar as part of the braising liquid. One of my favorites uses a blend of red wine and balsamic vinegar, and there's another that calls for sherry vinegar. I would suggest you simply give your braising liquid a quick taste. If it is a bit sharp for your taste, you can counter that with a bit of sugar, honey, or other sweetener. You can also convert some of the vinegar's acidity with a pinch of baking soda- just be careful not to use more than 1/8 teaspoon or so, because unreacted soda will taste soapy. Who knows- it might just turn out tasty as it is, and you will have a new recipe in your repertoire.

Not really. They'll probably still be good, however, you don't really want to make a brand new braising liquid for them two hours into the cook.