Hi Guys,

I have an AU 1 6cl Fairmont running duel fuel which has started playing up recently. Car cruises fine, however when braking, engins starts to shake and sometimes, but not always stalls. It does this on petrol or gas but more on gas and also idles rough. Feels like a vacuum leak to me but I can't find any leak.

Is there a way to check for vacuum leaks? If so I would appriciate your advice.

Check for vacuum leaks by spraying aerostart or similar over intake manifold whilst engine is idling. If revs increase there is a vacuum leak there. You can also do this around hoses.

check the hose goin from the airbox over the thermos to your gas converter, it may have dried up/or burnt and have some cracks/holes in it.

(before someone says this will only affect the gas, it can also affect on petrol as the ecu doesn't know what to do when braking if it has been driven on gas for a fair while and then switched to petrol until it relearns)

Thanks Guys. I appriciate your advice and will try your suggestions when I get back home. I'll keep you posted on results. Cheers