Hello ExileScooters and welcome to the forum.
I have a question for you: what grommets have you replaced, and why did you choose a much stiffer one? Was anything else changed? Some good quality pictures will help.
Sometimes changing parts causes unintended consequences. You might want to consider installing the original grommets if only to see if that changes anything.
Please let us know what you find.
Last edited by Eggman; 01-04-2018 at 09:04 AM.
View my fuel log 2015 Mirage ES 1.2 manual: 50.1 mpg (US) ... 21.3 km/L ... 4.7 L/100 km ... 60.2 mpg (Imp)