[Gasoline Fumes]

Part number should be on the ECM label. All late '94 Metros got the 4-wire O2 sensor, not just California versions. I have two '94 Metros with Federal emissions and both had the 4-wire O2 sensors.

The top of the label will have something like B4 or L1, or another letter/number code.

Next is the ECM description. My '92 XFi is: "3 - ER - FED"
3 = 3-cyl, 4 = 4-cyl
ER = XFi, MT = manual trans, AT = auto trans
FED = federal emissions, CAL = California emissions

Then you have the Suzuki and Denso part numbers.