El Falcon on duel fuel, idles poorly IE threatens to stall and despite adjusting bidle screw can:t seem to get the engine to idle higher than 750rpm. This problem presents itself both on LPG but worse on 92 pump fuel.
I have just replaced the spark plugs with Ford motocraft Denso plugs for duel fuel. Minimal if any improvement noticed.
If anyone can help I would really appreciate your input. This is my first time on this forum,
thanks,
elnick

Common problem is the idle speed controller filling up with s**t. Unbolt it from the TB (2x 10mm bolts), spray brakeclean into it and blow it out with compressed air.