Gasoline smell when engine cold and driving downhill

If you don't know the source of the gasoline smell, why would you go to the trouble of replacing the O rings? It would be better to identify the source before jumping into a repair like that only to find out after all that work, it still smells like fuel . you can loosen the fuel line fitting slightly to release pressure. I'd do that on a completely cold engine.

leak goimg to the engine bay area or cracked fuel tank.

Was this the smell of burnt fuel or raw gasoline? If this started after it began getting cold outside this can indicate a problem with the EVAP system in the car. This may or may not cause a check engine light.

This site reported a 2010 model of your car having this same symptom.
They found the injector seals to be leaking.
http://www.truedelta.com/Jaguar-XF/engine-problems-808
supercharged 510hp 5.0L V8 6-speed shiftable automatic RWD
Mar 2010 4340 0 injector seal leak causing "gas" smell in cabin - replaced injector and new seal kits on other injectors

That can be a very serious issue with the potential to cause a fire. I would have it checked by a professional mechanic and specify your concern on the injector seals being checked.

possibly your O rings which isolates fuel injectors from engine block are getting old and letting gasoline go out. it is very dangerous since it can cause fire. do not drive.

another cause is broken loose or cracked fuel lines. this is equally dangerous since it is under hood close to hot exhaust manifold.

if smell is from exhaust manifold, which means not the smeel of gasoline but exhaust fumes, this can be caused by broken exhaust manifold or a crack on it or problematic exhaust manifold gasket.

if this car is on the cold start injector when it is defective. Injects additional fuel to the engine is still warm. Is it to feel warm by running more than normal gasoline smell?

Sounds like a fuel leak from the fuel rail check the rail and the pipe that feeds it.You have a leak buddy and when your driving the smell gets blown away.

Some smell is normal if it has been quite sometime between oil changes. This happens more with short distance driving.

How does it get there?

Through cylinder blow by when the engine is cold. The piston rings leak minuscule amounts into the oil which add up over time.

If you are having no other running issues (IE black/drk grey smoke out tail pipe with oil residue on pipe tip) I would not be alarmed by this.

If it is running fine, the busted bolt isn't the source of the gasoline smell. The intake manifold has vacuum, so the smell wouldn't be getting out, air would be going in, and a vacuum leak would give you poor idling. The exhaust manifold wouldn't have much raw gasoline smell. But it would have loud noise if the broken bolt were causing an exhaust leak.

Check that the vapor recovery line is not broken or disconnected. The hose connectors get cracked. If that were broken, it would cause a gasoline smell after the car has been sitting, especially if it has been sitting in the sun, heat driving gasoline vapor out of the tank. It is supposed to condense in the vapor canister, but some escapes if the line is broken. If it is broken, driving would **** out the gasoline from the line and the wind would dissipate the smell.

Or it could be a leaking injector. With the injector cover off, engine idling and cool, you can visually look for raw gas around the injectors and injector rail connections.

Hope this helps.

this is very indicative of clogged catalytic converters,
i would also replace the 02 sensor.

hope2help

shack

I had same problem a month ago. I had the o-rings replaced on the fuel injectors... problem solved.