Regarding the UC schools, you can call the admissions office of one of those schools if you want to double check this. They will tell you the answer. However, on a tour of a few of the UC schools (SB, Berkeley, and LA), they said they treat all applicants equally as long as they are in the same college. Economics is in the College of Letters and Science, so as long as you get into that college, it does not matter if you are an Econ major or undeclared. Engineering is an impacted major at Berkeley (and probably every other school in the U.S.), and is usually in a different college (i.e., the College of Engineering). I guess what I am saying is that it is most likely more difficult to get into the Engineering major. I cannot speak for the CSU schools, other than to say my friend was able to get into Engineering at Cal Poly SLO with a GPA near yours.