Flickering oil light at idle and warm engine

Did you check oil pressure before and after pump change?

Pressure switches are located on top of the oil filter mount and there is also one in the end of the head on the drivers side. They are both single wire units unless you have a gauge in the dash in which case there will be 2 wires on the one in the filter mount. Replace them both and if that dosent solve the problem, remove the oil filter mount from the block and replace the oil control valve inside there. It needs to be loc-tited into place without glueing it shut. Both are quick cheap fixes.

The oil pressure switch at the head is the low pressure switch.

The oil pressure switch at the filter flange is the high pressure switch.

The low pressure switch causes the light to blink when the key
is in the ON position, or when oil pressure is less than 0.25bar
at low engine rpms.

The high pressure switch causes the light & buzzer to come on when
the engine is running and oil pressure is less than 1.8bar at 2000rpm
or above.

One the 1.8 & 2 liter engines, there is no control valve in the
filter mounting flange.

Oil pressure is controlled by the pressure relieve valve in the
oil pump.

Thomas