Is this situation possible?

Right now I’m at UCSC but I really don’t like it here. Is it possible to drop out of UCSC after the first year, then go to a CC, then apply to UCSD for electrical engineering?

How high must my gpa be if I want to apply for electrical engineering?

You could. Although it might be easier to stay two years at UCSC and transfer UC-UC.

But I heard transferring UC-UC for an engineering major is impossible?

You need to get advice that is more specific to your situation. Pay a visit to the Transfer Advisor at the CC you would be attending, and ask about the process.