This is just the fuel slopping about in the tank when the car comes to a stop.

A plastic tank under the back seat and probably no baffles except the saddle over the

transmision tunnel.

 

It wasn't long after the thumping sound started that I got an air suspension fault and have been having problems with the backside air suspension.

My elegant lady in her little black dress now looks like a city kid with baggy trousers hanging down the back.

 

I'm with P700 on this one. There have been reports in the UK of Jags where the tank has collapsed, split, and emptied its contents into the boot. The culprit is the EVAP system on the tank as under certain fault conditions it can be subjected to engine vacuum. It is an incredibly complicated system but the problem with it is that it injects (or draws) fuel vapours into the engine.

To test it though will be difficult. Just taking the filler cap off isn't good enough. It must be immediately after a (normal) run and with the engine still running. I would suggest that you remain in the car and someone else opens the filler. If it's an intermittent fault then it could be tedious to find.

 

How can the fuel get into the boot when the tank is under the back seats?

 

I get a thump coming from the back sometimes when I stop. But most of all I've been dealing with a P442 code"small leak in evap system". If I fuel up on my way home sometimes I will have a puddle of gas on the driveway in front of the driver side rear tire in the morning. If I fill up on my way to work this doesn't happen. I do not get the smell of gas in the cabin or trunk, just sometimes outside of the car