l had posted before about changing my O2 sensor on a 97 Subaru Legacy wagon with an OEM sensor and the check engine light came back. l received great responses (Thanks : )One of them wasto multi meter the wire coming from the engine side of the bank one sensor two oxygen sensor which sits right on the catalytic converter. l multi metered the wire using a positive and the negative with the ignition on engine off. There where three wires, two positive and one negative. l got a 10 ohm reading from one positive and no pulse from the other. Could this be the problem?

You have few (possible) problem. You will only get a reading when (a) the engine is running (b) O2 sensor is warmed up.

The only last problem is that digital multimeter (DMM) r often TOO SLOW to respond for u read the value. Some non-auto-ranging meters r little bit faster but by not much.

Some DMM have ''bar graph'' on top that can move as fast the pulse (even if the digital readout is still hunting). There r few LED bar-graph O2 (or exhaust gas oxygen - EGO) meter u can hook up. They r little more than 0-1 volt meter. But they react very quickly.
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Another thing is that u want to be reading the VOLTage not the resistance (ohm). When the engine is running at stoichiometry (14.7 : 1 - perfect air to fuel ratio) the voltage should be near 0.45. But in practice it should bounce little bit above & below that (about 3 to 10 times per second). But that is only during idle or cruise. At wide open throttle (WOT) the engine ignores the O2 sensor & just dumps fuel (at something like 12:1 A/F ration).

It sounds like the cats.