I took my 90 turbo 2 out last night, first problem was the tac wasnt work, and on the way home it began to run very rough. As my psi would build i heard a loud hissing noise, sounded like an air leak. Every time my rpm's would drop below 1000 the car would stall. I got it home, babying it all the way, only to find that the previous owner had used electrical tape to hold on the bov. my question is, could this have caused any serious engine damage?

 

Probably not. Any air leak will totally confuse the EFI system. Fix the leak and things will probably be fine.