Pierre Gasly will start the Mexican Grand Prix from the back of the grid after Honda opted to revert to its old spec engine ahead of the weekend. Gasly also received a penalty last weekend in the US, which knocked him back to the rear of the grid.
Minor modifications were made to the engine before the race in Austin, and now this weekend in Mexico, Honda decided to input a fresh engine as they "have a concern regarding the assembly of the one used in Austin”, according to their Technical Director Toyoharu Tanabe.
“That PU has been sent to Sakura for a full inspection and, at the moment, we are not sure if we can use it again this year. Therefore, by fitting a new one here, we add one to the pool of available units for the rest of this season,” he continued.
“From FP2 and for the rest of the weekend, Gasly will run an older specification PU. Brendon [Hartley] is also using this spec, for the entire weekend. The reason for reverting to the earlier pre-Russia spec is that we have a better understanding of this version of the PU and are more confident in our ability to set it up correctly for the specific conditions here in Mexico City.”
Toro Rosso is running with its upgrades on Hartley's car for the opening day of running as they assess the new parts. The new floor and front wing were used in Austin, however insufficient data was collected due to heavy rain on Friday.