Has anybody had problems with after market cats? We have nearly always fitted pattern cats when the need arises, and not had any problems, but the last couple we have fitted seem to log a fault after driving for up to 1000 miles.
The fault comes up as mixture to lean, but after checking lambda sensors etc, the only conclusion that we can come up with is the cat playing up.
This has occurred on a 51 plate 1.6 Focus and a 03 plate 1.6 Megane Scenic.