Engine warning light

[mayesj86]

Looking for some advice again.
Changed the plugs and coils (ngk's and r8 coils) and now the exhaust reduced emissions light has come on and stayed on. Car is running perfectly smooth with no missfires. Would this likely to be a lambda sensor fault or MAF? I have double checked the connections I touched and all are fine.
Cheers
Jason

[Shamm]

Have you got a standard exhaust? If so then at times the light will come on the dash but will go out later it self

[MIJ_JAGGER]

Have you got a standard exhaust? If so then at times the light will come on the dash but will go out later it self

Why would the light just come on at times?

[mayesj86]

Have you got a standard exhaust? If so then at times the light will come on the dash but will go out later it self

It has a standard downpipe and miltek cat back. Is it normal for the light to flick on and off? This is the first time it's happened in 12k miles.
Gave everything a double check and all is ok. Can't see it be the coils or plugs.
Thanks for the quick response.

[colesey]

Have you perhaps also filled the fuel tank right to the brim? I had the CEL come on once when doing that and it soon went back to normal once the overfill vapours had gone away.

[slix]

If a problem comes after fitting new parts then it's usually down to the parts or something you did whilst installing the parts.