High Co percentage on F355

[bestuning]

Dear Friends,
I have a F355 Year 1998 F1 Gearbox with complete Tuby exhaust system and one oxygen sensor on each bank. The Co percentage is around 8, is there a way to lower it down?
Thanks for any help.
Bernard.

[smg]

short answer no, the EFI is set with no adjustment. the high CO reading though is a marker that something is not right.
My first look would be the manifolds, they are known to crack and an exhaust leak will cause the ECM to 'adjust' and run a richer mixture hence the elevated CO.

do you have a check engine light? i'd also get to a shop with diagnostic eq and see if any codes are stored.

[bestuning]

Thanks for your help, I will check out the exhaust manifolds, your suggestion is very logic.