Both parts are identical, both have same threads, but 2 diff part numbers, would they both work or does the 2000 sensor have a different resistance and would give me a bad reading?

 

Not sure what the difference is but the '98 part number is still good, so has to be something - maybe the connector? I wouldn't take the chance using the 99-02 sensor.

 

the connectors are the same, even the threads, either its internally or they are the same, just like alot of LS1 intakes have different numbers but are all basically the same thing.

 

98 is a different sensor. It looks almost identical but the plug is NOT the same. It roughly the same shape, but if you look down into the 98 sensor and then on a 99 up sensor you will see they are different and can not interchange. I just had to replace mine on my 98 and trust me they are different. Make sure you order for 98