Does anyone know the effect of adding oxygenates such as MTBE to gasoline in terms of exhust emission testing. In winter time many parts of the US have to switch or add oxygenates to gasoline. I am wondering what effect that has when you take your car for emission testing. This is an interest to me since my car 92 400E just failed the HC part of the emission test (102 limit is 100).
Does make sense to store some gasoline from summer time then put it in the car before going for emission testing?