TPS61178EVM-792: Could not make the design for 5V/3A out

Dear expert, 

We want to use TPS61178 to do the 3~5V input to 5V/3A output. And we follow the webench design on our EVM but found that our output could not stable at 5V when there's any load. (We failed at light load 0.75A Vout becomes 4.4V and at full load 3A Vout becomes around 2V)

https://webench.ti.com/power-designer/switching-regulator/customize/123?VinMin=3&VinMax=3.3&O1V=5&O1I=3&base_pn=TPS61178&AppType=None&Flavor=None&op_TA=30&origin=pf_panel&lang_chosen=en-US&optfactor=3&Topology=Boost&flavor=None&VoltageOption=None

We tried to tune the compensation but still could not let output voltage stable at 5V with load. We have tried use 3.3uH/ 1uH/ 470nH inductor. And compensation components: besides the values recommend by webench, we also tried C6= 10pF, R5=1.8kohm, C5=220nF. 

Because we didn't find the calculation tool of this part and customer need to decide use this solution or not by tomorrow, may we have your help to recommend how we could tune the EVM to achieve customer's spec? 3~5V input to 5V/3A output

Thank you.

Best Regards.

Cindy