'Fuel Trim rich' below is for 95 but should be similar...If you need more info , send me an email..
Paul
DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic charts.

1. Visually/physically checking items which may cause a rich condition may determine the cause of DTC P0172 being set.
2. A mass air flow sensor that causes the PCM to read a higher than actual air flow can cause a rich condition and DTC P0172 to be set.
3. Silicon contamination of the Heated Oxygen Sensor (HO2S) can cause a false rich indication to be seen by the PCM. The PCM will then reduce the amount of the fuel delivered, possibly causing severe driveablity symptoms.