325i high CO & HC

My 1990 325i has high CO & HC.
The cyl head has been reconditioned and new HT Leads ,plugs, dizzy cap, rotar arm have been fitted.
Full diagnostick checks don,t show any problems apart from the high HC & CO.
There are no fault codes on the ecu.
Airflow meter was suspected.
2 factory recon airflow meters were fitted, both gave extremly high HC & CO and would not adjust enough to reduce the levels.
A new BMW airflow meter was fitted and gave extremly low HC & CO and would not adjust enough to run properly.
Any ideas Pleeeese.

There's a connector [ C191 ] under the throttle housing, check it for corrosion. Also check fuel pressure.