How to Diagnose Possible Oxygen Sensor Problem?

[lavabit]

I've been trying to diagnose an intermittent poor engine running problem that seems to occur only after the engine has warmed up.

Can the ecm be made to run in open loop mode (ignoring oxygen sensor) by taking the connector off the temp sensor or if that doesn't work then by putting a resistor across the electrical connector in place of the temp sensor to fool the ecm into thinking the engine is always running cold?

Are there any other ways to isolate or to test the oxygen sensor to avoid buying a new one that might be unnecessary?

update: I disconnected wire from oxygen sensor. Engine did still run. Ran same as before including the intermittent missing problem once engine had run for about 30 or 40 minutes, so problem is not the oxygen sensor.

[tahiti350]

When I got my white wagon teh O2 sensor wire had gotten caught on the half shaft adn ton out fo the sensor. P.O. (my father-in-law) had been driving it like that for over a year and getting almost the same milage.....

Try disconnecting it and see what it does, worst that can happen is it runs worse adn you have to reset the computer to clear the fault.