A multi-vehicle chassis dynamometer procedure for evaluating an engine oil for fuel economy effects has been accepted by ASTM and the lubrication industry with reservation. The reservation stems from the high test cost, the poor repeatability/reproducibility, and a concern that some additive chemistries are not being fairly evaluated. Recognizing these concerns, ASTM Committee D-2 has agreed to continue development work, but the thrust will now be toward a Sequence type, dynamometer engine test. The work which will be described here is part of a statistically designed study intended to screen operating conditions and hardware for their effects on fuel efficiency and test reliability. Three ASTM FEEO oils were evaluated relative to the FEEO reference oil HR-2 in a 2.8 L V-6 engine. Correlation with results from the 5-car test development program will be presented, as well as the results of the analysis for operating condition effects and sources of test variability.