Will O2 sensor cause rough idle?

[tykeeus]

I have a 94 Q45 with the O2 sensor light on. It has a rough idle. Is that caused by the O2 sensor? I ordered replacements, but want to make sure there is not something else I need to check.

[elwesso]

no it shouldnt. o2 sensors are only used during certain times and they are only used to monitor AF ratios, and can only adjust them by +/- 20% or so...... they have no effect on the idle quality.

[tykeeus]

So what would cause a mold rough idle, but fine at cruise? I checked for codes, but there were none. The car sat for 6 months before I bought it. Possibly plugs and a tune up?

[tykeeus]

That is a MILD rough idle.

[T45]

You need to OHM your injectors, run some BG44K through the fuel system, and if you haven't done so already, fill up the fuel tank with fresh 93. Also check the IAC but it's probably an injector.