This mixed methods study investigated a college engineering professor’s first-time implementation of project/problem-based instruction (PBI) within an engineering mechanics (EM) course and compared this implementation with a business-as-usual (BAU) EM course. Research questions concerned the degree to which the PBI course changed from a BAU model and the effectiveness of the PBI implementation on students’ EM learning as measured by a Statics Concept Inventory as compared to BAU students. Findings showed the professor’s original intentions and realizations of project-based instruction had to be adjusted to a problem-based instructional format to keep it in line with the EM course objectives (simply better suited as problem-based).