I don't remember the model number of the Denso 4-wire o2 I have now. I have an extra Denso 4-wire I picked up for my truck (96 chevy v8) that I ended up not needing for whatever reason it was, but I don't know if the resistance/calibration/readings/whatever would be the same for the 89 v6 even though the threads are the same. If it turned out to be compatable, I could pick up a 4-wire plug and make life much easier next time around.

Those of you with a 4-wire o2, what model# are you using? Didn't really find much searching.

Trying to find one for this car online only brings up single wire o2s. (I have headers and need the heated o2 or I get o2 codes)

 

Im running a 4 wire O2 on mine. You just have to make sure your signal wire is going to the right place. For power, i tapped into the MAF power wire. The other 2 black wires are grounds. It is a good idea to ground each black wire to a seperate ground location. I have been running mine for about 3 months with no issues whatsoever. I have a Bosch style one. I robbed it off a Ford at the U-pull yard.