I have a 1998 Explorer (6 cyl, 2wd) and my upstream oxygen sensors are going bad. Is this something a novice can change? Are there any special tools needed? If so, how do I go about changing this? Any info on this would be appreciated?
Yes, this can often be a simple DIY job provided you have easy access to the sensors. If so it is just a bolt-off, bolt-on operation. No special tools are required, but a special oxygen sensor socket can simplify matters. A set of such sockets is available free from Advance Auto’s Loan-a-Tool program. See here:
http://www.autozone.com/in_our_stores/loan_a_tool/exhaust/oxygen_sensor_wrench_set.htm
If your O2 sensors are in a hard-to-access location, if your vehicle needs to go on a lift for access, you may be better off letting a shop handle the job.