nervous fuel mixture gauge

[6fire]

My 87 GN has a rich/lean gauge that is wired to the O2 sensor, and it never reaches a stable setting. The lights scan back and forth from rich to lean to rich...etc... Shouldn't this stay stable after the engine warms up? The car has a new heated O2 sensor with only 3k miles on it. Also, any pushing of the accelerator pedal over 1/2, or any boost sends the lights well into the red (rich).

I have no experience in tuning these engines. Is this the way the fuel mapping is supposed to behave?

 

[Black Car]

No, the gauge is suppose to jump back and forth untill you go WOT.
The reason is that the computer is trying to maintance the A/F ratio being called for in the chip when you aren't in power enrichment or WOT mode. i.e. not got you foot into it heavy.

Gary

 

[305turbo]

What you described sounds normal to me. The O2 is supposed to be switching between lean and rich. If it stays constant or switches slowly then the O2 sensor is screwed.

 

[Joe 1320]

Yup... what they already said. What I can add is that if it goes to a steady state when at idle, your 02 sensor is on the way out or you are way past a point that the computer can compensate.