fuel problems...

[A-J]

1.8 spi, doesnt seem to like any other fuel other than shell, and even when its run thru a few tanks theres still the odd flat spot. i've got the octane plug on 95, and now my brothers driving about in the car i'd like to know its going to keep going (he doesnt have a mechanical scooby)

any help appreciated

[Envoy CDX]

When was the last time the fuel filter was changed?
I've had issues where the car ran better on some fuels and not very well on others.

Look at the fuel filter (probably fairly old as it's rare people change them), then look at your general serviceable items, plugs, leads and that kind of thing.

[A-J]

all filters, plugs, leads etc i replaced when i bought the car last october, one of the first things i did.

[Envoy CDX]

Maybe timing related?

Certainly a strange one for it to only be running on certain fuel.

[Squig]

possibility that the flat spots are related to injector spray pattern, try having it cleaned (probably about £20 as a set is usually £60).