ok so i am having some new issues with my 1995 non sc riviera. it seems that when my car is idleing for more than 5 or 10 mins i will get a service engine code saying O2 sensor low circuite. however i can be driveing either around town or on the highway for any amout of time and get no codes at all? any help or ideas as to what can be causeing this. the first thing i tried was to replace O2 sensor figureing that may of been the problym but had no luck.

What is the exact code?
Probably have to check and test all related electrical connections per the FSM.
Also look for any chafed or burned wires. Sometimes you get lucky and find the problem in an easy to repair area.

Generally it's correct, your O2 is getting "lazy". If that's not it, do you have any exhaust leaks, even tiny ones?

I got a bad Delphi sensor new out of the box, when i did my headers recently, but it tripped a code for "insufficient switching".
After looking at the signal on a lab scope, it was very lazy and erratic at lower RPM's and good at higher RPM's.
Had to get another Delphi unit.
It is not uncommon to get bad ones new. They can be mishandled / dropped during shipping and mess them up.

thank ill get the exact code tommorow before i head to work, i dont know if it may be related but the only other issue i am haveing with this car is that the idle seems to be a little rough at times, but other times its perfect. this seems to be most noticeable when im stoped at a light and the car is in drive.

What brand is your replacement O2? I have heard of a lot of 'lazy' issues with many aftermarket O2 sensors, and that a Delco O2 sensor solved the problem.

thanks i will checkthat out today when i get home from work, can this be affecting the roughness in my idle. also when you say "lazy" what does that mean?

http://www.google.com/search?client=safari&rls=en-us&q=lazy+O2+sensor&ie=UTF-8&oe=UTF-8

It means the O2 sensor is not creating enough cross-counts for the exhaust pulses.

can that be giveing me a rough idle?

Yes

is there any way to test the o2 sensor to see if it is being "lazy"

With a computer you could observe the cross-counts. Not an easy thing to do...

Check for big vacuum leaks, spray around the throttle body and intake manifold with some carb cleaner and see if you affect the way the engine runs. Make sure all vacuum lines are connected properly. This could be causing a lean condition that's being misinterpreted by the computer.

thanks again, i have a computer to read the live data, what would i be looking for in the cross-counts that would indicate a problym with the sensor

Not enough of them. I don't know what that value is, but there should be a cross-count for each exhaust pulse, it's looking for a certain number per second as a minimum. I'm afraid I can't be any more technical than that, as I'm not sure what the values are supposed to be, or where to look in the computer for them, or if you can even see that value in the computer!

Anyone know if AllData or one of the other online tech subscriptions has this info?

so i replaced the o2 sensor finially btut i am still haveing the same problym the code p0131 o2 signal to low keeps comeing back when my car is at idle does any one have any other suggestions,