I am a member of a multi-member LLC. The LLC filed an extension for its 2017 tax return (Form 7004). As a member of the LLC, does this mean by default that I have to file a personal extension since the K-1 from the LLC is not yet available?
By all means, file for an extension. The important thing is to pay by today 4/17. For this you will need to (over?)estimate the K1 income numbers in order to know how much to send the IRS with your extension form. And don't forget your state income tax return(s) if any.