Ether ...... If you're spraying it about under the bonnet (rather than into the intake) ... the stuff is very inflammable ... which is why it's such a useful diagnostic tool 🙂 .... you can also get woozy on it (it was used as an anaesthetic back in the day after all) ... outside on the drive is a good precaution and the ventilation solves the major part of both the above observations.
K
