I had a massive problem with my CO content. It was up to 9.45. This was caused my the ECU being chipped badly before I owned the car. The result was that it drank fuel, and spat alot of it out of the exhaust, and caused compression problems by glazing the cylinder walls. I had to remove the head, sump and pistons to replace the rings and service the cylinders. I also gave the head a skim and service too.
I replaced the ECU after more trouble shooting and now I have a very powerfull 8v which I'm very pleased with.
High emissions will not effect idle if the idle is set to match the mixture. To set up the engine properly, first you need to check and set the ignition timing. This must be done first. Then you need a CO gas analiser (Spelling??

) and set the mixture and idle at the same time as per the imfamous guide. The reading should be between 1.0-1.5, but generally it is set at 2.0-2.5. The limit is 3.5. As you can see, mine was off the richter scale, but now its down to 1.2.
Actually, today I am going to re-adjust mine as when the aircon is on, the revs faid away to a stall.
Hope this helps.
