First of guys, apologies for coming on here and asking for help without any prior contribution to this forum.

I am getting a gassy (not petrol for the US contributors) smell, almost like natural gas, from the rear of my 2003 Gallardo after the engine has stopped. I suspect cat failure but has anyone had this before?

Thanks you in advance

Russ Treasure

Need much more detail. is it a new car? Oil changed/ any oil on floor? Engine running OK? e-gear/manual. Used clutch? etc....

OK no problem.

It is a 2003 car which I have had from new. Everything else is perfect but the clutch is probably due for renewal although not slipping. I have noticed now that the smell is now noticable inside the car as well.

de-cat the car, see how it is then.

By the meaning of gassy like natural gas, does it smell like rotten eggs?
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There Is A Rotten Egg Smell Coming From The Exhaust:
Whenever you run the engine and are not moving, you notice an awful smell from the exhaust. The smell is like that of rotten eggs. Not only do you notice this, so does everyone around your car. You may also have noticed that your gas mileage has been worse lately.
Possible causes:
1. There is a problem with your electronic engine control system: Scan injection and emission control system for Diagnostic Trouble codes. Replace or repair as required.
2. The ignition timing may be set wrong: Check and adjust ignition timing.
3. Your fuel pressure regulator is bad: Replace the fuel pressure regulator.
4. The engine may have mechanical problems: Check vacuum lines and fittings for leaks. Check engine compression. Check for broken fittings and mounts.
5. The engine is running too hot: Check cooling system, thermostat and cooling fanes for proper operation

Yes I know what you mean about the cats but it is definitely a smell like natural gas rather than rotten eggs. If I decat it surely it will not pass the next MOT test?

Cheers
Russ

Is this with just one tank of gas. If you refill does smell remain. Bad gas?