Q: High CO2 emissions on a '98 Mitsubishi Carisma

Often it’s a GDI because they carbon up the engines over time. Pay a mechanic to carbon clean the entire engine. Then you’d want to pray that the cat hasn’t been ruined. It may already be ruined. It’s a ’98 so it’s really old. Have the engine carbon cleaned first. Start there. Still, you might need a new catalytic converter because of the age. It had been throwing oil in the engine and carbon’ing up. If it clogged up the catalytic converter with carbon, it needs a replacement. If you want to have this looked at by a certified technician, a certified mechanic from YourMechanic can inspect your vehicle and replace your catalytic converter for you if necessary.