My car randomly started sputtering maybe two days ago. So I was thinking maybe the opti was giving out because it gave me DTC 16 a while back but hasn't happened again. But now I'm thinking it maybe the new Bosch o2 sensor on the right side because I was using freescan on the way home and noticed that while my car was running good and normal everything checked out okay, but it gave me DTC 18 which is listed as unused. Then when it started running bad by what seems like a missing and sputtering I saw the right o2's voltage was less than 80mV while the left one was at 300mV. Then shortly after the right o2 sensor's voltage hopped back up and my car ran good again. I was wondering what DTC 18 was? and what could cause the right o2 voltage to drop like that? I'm thinking of replacing both o2s with the Delco version tomorrow and was wondering if that would fix my problem of does it sound like a wiring issue?

 

We could go into a big long discussion regarding 02 such as them always varying constantly and if you took your readings in open or closed loop. Very cheap and good maintenance to just replace them both. You can also switch them and see if the bank issues change with O2's then.

In the meantime, it is very obvious that if you threw a DTC 16 at some time in the past, you have to focus on the opti.

 

For starters, use the correct trouble code list. Shoebox has an LT1-specific list on his website.

http://shbox.com/1/Dtcs.htm

If you had looked at that, you would see that DTC 18 = faulty fuel injector circuit. It probably an injector on the right side, since that's the side that is reading lean. Check for +12V at each of the pink wires in the injector harness clips (key on). Check the resistance of each injector. Should be in the range of 12-15 ohms. Use a 'noid light to verify the PCM is providing the ground to fire the injector. Since it appears to be an intermittent problem, it may be hard to find. If that's the case, swap one injector at a time from the right side to the left side and see which one moves the low O2 readings to the left side.

Finding a stored DTC 16 is very common. I believe it sets on cold start when the PCM has a minor problem finding the low res pulse from the Opti. You clear it and if doesn't come back quickly, it tends to indicate its not an Opti problem.

 

I got the alternator replaced because it was whippling my mechanic says (voltage amplitude is too high or something like that). Seems to have cleared up, but he said if that didn't solve it maybe the computer wasn't giving the injectors the correct signal because while the car was acting up he unplugged an injector harness and the car wasn't effected.

 

"whippling" ??????

 

I don't know, lol that's what his computer labeled it. He said the voltage varied a lot causing AC sine curve. It seems to run a lot better now and my pulsing lights and jumping volt meter were cured along with the sputtering. I still think I have a small electrical problem somewhere but now it's much better.

 

If you have a significant AC component in the alternator's DC output, it will cause problems.

 

Yea everything seems to have gotten better, but still a little off.