So I just started running my Seat Leon 1.8t on E85 a few weeks ago after changing to Bosch Green Giant 440cc injectors. No other mods or tuning so far, apart from slightly more boost since before the conversion. The car has been hard to start in the mornings, but has been running great. I havn't managed to check the fuel trims yet, but everything I usually log with ME7Logger looks good.

Now it has died on me a few times. The engine just stops responding to the gas pedal, and when I put it in neutral it completely stops. It seems to only happen at highway speed, and if I just turn the ignition off and on to crank it again, it starts fine.

I'm guessing the fuel pump has a problem with E85, but just wanted to check if anyone has any other ideas? Or is it just a coincidence that the problem showed up when I switched to E85? The only trouble code I have is something with "brake light switch, implausible signal".