I have a problem with my front O2 sensor on my 1991 VR-4.
After the car has warmed up and I drive in fourth or fifth gear at around 2000 rpm (+/- 100rpm) and the vacuum/boost gauge reads about 5psi (+/-1 psi), the Check Engine Light will go on. I need to cruise constantly for several minutes under the above conditions for the CEL to turn on. Checking the code in my manual, it reveals a problem with the front O2 sensor. The car has about 91k miles on it.
To characterize this problem, I clear the CEL by disconnecting the battery for 10 seconds. Mileage has not decreased from 20-21mpg.
-is this sensor difficult to replace (how many hours by a mechanic, can I do it myself with simple tools and a sensor wrench)?
-any other comments to help me resolve this?