Second hand car from car giant

[Carman6]

Hi everybody, I purchased a car from car giant on July 2nd this year and I noticed a smell in the car like eggy Sulphur like smell someone said it sounds like catalyic* converter is on the blink so I told car giant and they said get the car checked at a garage so I had the car looked at and they said nothing is showing up on scan but we could change pollen filter and a valve that might help and it seemed to help but it was smelling a little bit still no warning light on dash board until now it, s showing a p0420 code which is cat converter problem now car giant say I have done 16 or 17000 miles and they can't cover that they only cover up to 5000 miles is this within my consumer rights as I am now worried as this is an mot fail and an expensive job. Any help would be much appreciated. Thank you

[Carman6]

Hi everybody, I purchased a car from car giant on July 2nd this year and I noticed a smell in the car like eggy Sulphur like smell someone said it sounds like catalyic converter is on the blink so I told car giant and they said get the car checked at a garage so I had the car looked at and they said nothing is showing up on scan but we could change pollen filter and a valve that might help and it seemed to help but it was smelling a little bit still no warning light on dash board until now it, s showing a p0420 code which is cat converter problem now car giant say I have done 16 or 17000 miles and they can't cover that they only cover up to 5000 miles is this within my consumer rights as I am now worried as this is an mot fail and an expensive job. Any help would be much appreciated. Thank you