http://www.grandprixforums.net/websi...C/1997-L36.pdf

O2S Heater Circuit
Malfunction (Bank 1,
Sensor 2)
P0141

This DTC determines if
the O2 sensor heater is
functioning properly by
monitoring the amount of
time necessary for the O2
sensor to become active
after start - up.

The elapsed time to obtain 0.150V
from the mean O2 bias voltage.
*Time based on table: Time vs Start
Up Coolant Temp.
ECT < 35C
IAT < 35C
ECT-IAT 6C
Avg MAF < 20 gps
From cold start to a maximum
time of 330 seconds.
*Time determined by table.
once per key cycle
DTC Type
B
Could be failing sensors by the description above.

GM (AC Delco) sensors are the best ones.

But pricey.

Denso's are a less expensive but comparable option.