I'm with linquest on this one. I generally encourage engineers to go for it, you are a popular breed among law firms, but law school is a beast of its own. Going to law school if you are uncertain about wanting to be a lawyer is just, in appropriate internet speak, epic fail.
I firmly believe you cannot succeed in law school without having a passion for what you will be doing.
And, on a separate but related note, making any form of career decision based on "want to make more money" is also very likely to be a disaster. Money follows from success.