I just replaced the oxygen sensor on my '95 SSEi with 91k, wasn't having any drivability problems, just didn't think milage was good enough, and from many posts here seems this sensor is just something that wears out over time/usage. Haven't used up a tank yet, so don't know if milage improvement yet, but something I noticed right away, is idle speed. I didn't touch anything else, just replaced sensor, and my idle speed is up about 150 rpm (hard to tell exactly with stock insrument cluster tach, but it is noticable). Is this normal?
I used a delco AFS-75 GM PN 25312184, cost me $80 cdn. I'd never done a "repair" like this before, to change it I first pulled the retainer pin which locks the 2 halfs of the connecter together (with pliers), then pulled the connector off the bracket (with pliers) and broke the clip, but the new sensor comes with clip, then using 7/8 inch - 6 point 3 3/4 inch long sensor socket (cost me $24 cdn), but couldn't get entension on socket because sensor is just tilted back enough so there'* not enough clearance (how much extra would it have been for Pontiac to design the exhaust manifold so the sensor would be straight up), so off to Canadian Tire for a 1/2 inch universal joint (cost me $10 cdn), then break sensor loose, remove by hand, thread in new sensor, torque to 30 ft lbs, reconnect connector, insert retainer pin, clip back onto bracket.
1995 White Bonneville SSEi