Hi, i have a 2003 i.4 zetec fester.

The engine light illuminated a few months ago and was diagnosed by GK Ford Carlisle as having a blocked cat, we had a cat fitted supplied by TMS motor spares, about a month later the light has come back on and Ford have diagnosed once again a faulty cat, is there any common faults with the mk6 that would cause it to damage cats i.e. running rich etc, it does use a very small amount of oil but nothing other than normal usage, it had new lambda sensors, plugs and ht leads when cat was fitted, it's currently on very thin ice as we've had it 4 months with nothing but trouble!, cheers.

Hi, i have a 2003 i.4 zetec fester.

The engine light illuminated a few months ago and was diagnosed by GK Ford Carlisle as having a blocked cat, we had a cat fitted supplied by TMS motor spares, about a month later the light has come back on and Ford have diagnosed once again a faulty cat, is there any common faults with the mk6 that would cause it to damage cats i.e. running rich etc, it does use a very small amount of oil but nothing other than normal usage, it had new lambda sensors, plugs and ht leads when cat was fitted, it's currently on very thin ice as we've had it 4 months with nothing but trouble!, cheers.

You may be getting codes for the Cat but has anyone looked into a possible oxygen sensor? Also if your Cat is faulty it should not pass an emmission test. Has this been checked? another possible concern could be with the PCM given a false reading, causing the DTC tp be logged. Try an emmission test first then look at the oxygen sensors.

Good luck

Probably oxygen sensor failed as these don't last forever. ( normally several years ).

The first you'll know is the car will fail an mot emissions test and chances are they'll 'suggest' a new cat will cure it !!! ( more expensive..go figure )

I saw u said it had a new lambda sensor, are you 100% sure they actually changed it?( even if they did change it the new one could be 'duff' )

My sons car failed it's emissions during an mot and the mechanic said they`d changed everything cept the cat so we tried a new cat....still failed!

It was only when i asked in front of the garage owner the mechanic admitted he had never changed the sensor in the first place..........one new sensor later and the car passed it's emissions test!

Either way, if the new cat has supposedly failed get them to replace it under warranty and i bet miraculously they say it's the oxygen sensor, in which case ask why they changed the cat in the first place!