I am looking to apply next year and have a 3.7 GPA and a 34 on the ACT. I am wondering if applying to the engineering school lowers my chances of being accepted?
According to the latest Bucknell Common Data Set, the overall acceptance rate was 29.9%, and the 25-75% ACT range was 28-32.
https://www.bucknell.edu/Documents/InstitutionalResearch/CDS_2016-17/CDS_2016-17C.pdf
According to the latest ASEE profile, the acceptance rate for Bucknell engineering specifically was lower at 23.6%, and the ACT range was higher at 29-33.
http://profiles.asee.org/profiles/7382/screen/19?school_name=Bucknell+University
So yes, engineering at Bucknell is particularly competitive (this is typical at other schools as well). On the other hand, a 34 ACT should be a very competitive score at Bucknell, even for engineering.
You would easily get in.