Help me figure this one out, please...

**TGrits10** · 06-15-2006, 12:23 PM

Car has been missing intermittently lately, but it only comes at light throttle; Coasting or any more than a little throttle keeps it away.
It seems to be related to heat somewhat, as it doesn't do it when the engine is cold, and does it especially when the engine is hot.
I haven't noticed any change in gas mileage, btw.

I stopped by Autozone and pulled the codes, here's what I got:
-P0131 - O2 Sensor Circuit Low Volts Bank 1 Sensor 1
-P1133 - Manufacturer Controlled Fuel + Air Metering
-P0131(pd) - O2 Sensor Circuit Low Volts Bank 1 Sensor 1
-P0161(pd) - O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 2

The P1133 is a no-brainer thanks to the O2 sensor codes, and the P0161 doesn't look critical, so I'll ignore those two

The real issue seems to be the P0131, which I have with and without the 'pd'. I take it the 'pd' is the equivalent of 'H' for 'historical'?

OK so the obvious answer is that the Bank 1 pre-cat O2 sensor has gone bad, and replacing that will solve the problem.

HOWEVER....

I just replaced both pre-cat O2 sensors due to similar symptoms less than 10k miles ago, late last year IIRC. So I'm thinking there's something else going on that is eating my Bank 1 O2 sensors (last time only the Driver's Side sensor was black with carbon, the passenger side one looked fine, but I replaced it anyway.).

SO....

What could be eating my O2 sensors without causing any other symptoms or throwing any codes (Assuming the dying sensor is to blame for the miss)??????

TIA, this computer-controlled ignition stuff routinely baffles me....

**ninobrn99** · 06-15-2006, 02:42 PM

are you sure the wires didnt get burnt on the harness itself? do u have o2 extensions? if so, move it over to the pass. side and see if it follows..

**TGrits10** · 06-15-2006, 02:47 PM

Originally Posted by ninobrn99

are you sure the wires didnt get burnt on the harness itself? do u have o2 extensions? if so, move it over to the pass. side and see if it follows..

hmmmm

no O2 extensions, but it's possible the wire could be damaged, I haven't looked at that. How much of a PITA is it to swap the harnesses side to side??

**ninobrn99** · 06-15-2006, 02:50 PM

the harness itself, i dont know. i think if its messed up, your gonna have to cut, soilder and shield it. It could be that the wire is exposed and touching on something that keeps shorting out the sensor..

**TGrits10** · 06-15-2006, 03:01 PM

hrmmmm....I guess I'll replace the sensor since it'll need it anyway, and while I'm under there I'll give the harness a real good once over. Worst case scenario I guess is I never figure out what's eating my O2 sensors, and I have to replace one now and then.

**ninobrn99** · 06-15-2006, 03:05 PM

screw that! they cost too much to look at it that way. good luck figuring it out though.

**TGrits10** · 06-15-2006, 03:36 PM

well yeah $100 is $100 (or however much they cost, I forget). But put it in perspective. If I replace one every 10k miles, that's once every 40 tanks of gas. Call it $40 for a tank of gas, that's $1600, so with the O2 sensor as a consumable it's $1700...not a big difference.....of course that's assuming it lasts 10k miles, which it may not. What if I have a bad coil or injector or something hard to find like that? I've chased crap like this before, it's so much stress and frustration, if the problem isn't obvious (like a nice helpful computer code or a scorched O2 harness), I'd just as soon buy a sensor now and then to avoid dealing with it.

**sunsetorangess** · 06-16-2006, 01:17 PM

lol good outlook but if you catch a problem while its small you can fix it but if you let it go it could lead into bigger more expensive problems.

**NinerSevenTango** · 06-16-2006, 06:57 PM

Spark plugs and leads? Silicone gasket sealant? Oil consumption? Air filter leak? Injector sticking open?

Have fun,

--97T--

**TGrits10** · 06-17-2006, 11:31 AM

Originally Posted by NinerSevenTango

Spark plugs and leads? Silicone gasket sealant? Oil consumption? Air filter leak? Injector sticking open?

Have fun,

--97T--

Heh, yeah. That's exactly why I'm not chasing this one. I don't plan to keep the car much longer, and it could be anything....so it's much less headache to just replace the sensor whenever it's needed.