Got a 1.2 16v 2005 clio as a project and iv decided to decat it. Iv removed the cat smashed the insides out and welded a pipe inside. On idle after a while it will start to idle bad to the point it wants to cut out. I removed both 02 sensors and it idle better for longer but eventuall it started idling bad again. Im pretty sure its the second o2 sensor detecting no catalist so is messing air/fuel ratios at idle. I was thinking in making a mini cat that screws on to were the second o2 sensor screws to then screw the o2 sensor into the mini cat(piece of catalist in front of o2 sensor) so basically the o2 sensors sniffs the converted exaust gas and ecu thinks cat is there and hopfully this will fix the idle problem. I just wanted to ask before i weld away. One thing to note is they sell a decat pipe and it was both o2 sensor on them but they also have bolts in them.