Posted about this a while back. But still got problems so looking for new ideas.
In warm weather (ie ambient temp >23°C) i get an issue where if i rev the engine or drive along, then disengage the clutch and allow the revs to settle to idle they don't; Initially the revs stick around 1500rpm the slowly fall to about 1000rpm then dip/climb between idle speed and 1000rpm in an erratic fashion. This is even worse when the Air Con is on.
Ok, so there is some sort of problem with load correction and throttle control.
To rectify this i've tried:
Resetting the ECU
Cleaning the TB and doing a TB Alignment
Replaced the Coolant Temp Sensor
Replaced the MAF
Replaced the DV
Replaced most of the hoses with silicone ones
The only other obvious thing to try is replacing the N75, how much do these cost?
Does anyone have any other ideas?