If you mean a "bitter" tomato-y taste, I know exactly what you mean...
I use 1/2 tsp of baking soda to neutralize the acidity and add fresh basil. It will foam up and feel like you're in the middle of a mad scientist experiment for about 10 seconds. Then the foam goes away. Let it sit for an hour or so to soften the taste.
I've also floated a tablespoon of butter in hot sauce to tone it down. Don't boil it so it doesn't separate.
I'm of the opinion that tomatoes just aren't as tasty any more. This seems to happen more often than not with my sauce and I'm pretty darned tired of it.