Yaris with High CO Emissions & Code P0172

[hambleton1]

Hi All,

My 1.0L 1999 Yaris had high CO emissions on the MOT report, it passed but was right on the limit. I also used Cataclean before that but obviously it didn't help very much. That was in March, and now a fault code has come up: P0172 System Too Rich. I tried using premium unleaded fuel for a few weeks but the code keeps coming back after I reset it.

Does anyone have any ideas as to what is causing these issues? I have attached the emissions report for more detail.

Thank You :)

[Madasafish]

Some basic questions:

1. When last serviced? Date , miles then, miles now

 

 

Air filter blocked? Change it

MAF sensor dirty? clean it.. (see You tube and take great care)

 

Neither of those show a fault code but will result in a rich running engine..

[Verbal Kint]

It passed so no urgent problem at least.

As mentioned clean the MAF, use electrical contact cleaner.

Check for leaks, at this stage you might just have a small one upsetting things. Check for leaks around the cover gasket and intake manifold.

Check the intake pipe to the air filter is clear.

Check the wiring to the injectors are good.

Take the plugs out and check their condition.