In changing the o2, the fuse is located in the power center, check that fuse, also a bulletin about weird electrical problems exists, two grounds are to be cleaned and tightened(both sides of dash, right and left. The speedo driver is in the cluster, and gets its speed signal from the powertrain control mudule. Sometimes, any fuse out, mixes the PCM into a false reading internally, if you scan the whole PCM it will show speed info. On the scanner, and also all the communication modules wiring. And even in 98, quite a few. How is your speed control operating?
Check the fuses(both locations, interior and power center), grounds, and scan the speed externally. Funny though, because you have just been into the vehicle speed information source harness.
Tuesday, November 24th, 2009 AT 9:40 PM