One problem related to fuel hoses lines/piping and fittings has been reported for the 1999 BMW 740. The most recently reported issues are listed below.
Leaking fuel line in engine compartment close to exhaust. Leaking fuel is also vaporized and fumes get into vehicle and cause discomfort and nausea. Fumes could ignite harming occupants and others on the roadway. This is very common for owners of the BMW e38 and many other models. What I have found is a defective clamp/clamps on the passenger side of engine compartment on right hand drive models. Contacted BMW na for help on issue. No help.