my ef falcon gli runs duel fuel currently i had some problems other day with running petrol was idling very rough checked for a vaccuum leak found a broken f shaped connector running from crank ventilation hose under manifold back into the inlet manifold just underneath the throttle body replaced with all brass fittings still idles horribly rough on petrol also when running on gas once i hit about 2krpm and start to accelerate out it bogs down and nearly stalls also turning through roundabouts the car bogs down loses rpm and sometimes fires up again this happend today running on petrol aswell then the car wouldnt start i eventually got it running again but it seems to be happening alot lately any suggestions ???

You need to narrow down the possible causes by checking a few things:

1. Have you filled up your car with dodgy fuel? Maybe you've got water, diesel or crap in it.
2. Check your fuel filter and see if it's blocked
3. Check the condition of the spark plugs
4. Check if there's any loose plug lead connections (at the plugs and coil packs)
5. Check your injectors. I've seen a few blocked on dual fuel engines.

Hope this give you a starting point before spending money unnecessarily.

Id give a nulon injector cleaner a go with half a tank of 98, for the sake of $15 max for the injector cleaner its worth its weight in gold. Just drop it in before you drop the fuel in and run it on petrol until it gets to a low fuel level your comfortable with

aight cheers ill start narrowing down the possibilities thanks guys ill let you know how i go also to change coil pack on ef do i have to take the inlet manifold off ? looks like a b**ch to get to same thing with my ed was right underneath manifold but they have dizzy

I did mine without taking the manifold off. It was tricky and having the replacement infront of you to see were the mounting screws are helps. Can be done though, slide your arm under and around the a/c compressor and also from underneath. I found from underneath if you position yourself behind the bellhousing and reach up above the k frame from there was the best angle. Would save alot of stuffing around involved in dropping the manifold. If they need to be done and you decide to go ahead and drop the manifold, may aswell replace the leads while your at it and then do the plugs too.
Just a thought too, every dual fuel car I have owned in the past has had issues if there is the slightest air leak or vacuum leak. Could it be that maybe your manifold gaskets shot or maybe the vacuum hoses you were talking about are perished?