Random CEL codes

[zyxelenator]

Need advice guys. I'll try to tell long story short.
Since I got Scan Gauge it alarms me about pending codes. I had engine light lit up ones or twice actually. First code that was popping up was p0171 Lean code (System to lean bank1).
Then I had couple random misfire codes P0300, P0301, P0303 (which mostly show up in pairs).
Pending Codes will pop up randomly every day, or ones a week. They go away by themselves most time, since I just snooze alarm if I'm driving. They pop up mostly at idle. And seem more to popup at start up in the cold mornings.
First I thought it is vacuum leak since I forgot to install metal gasket between intake manifold and throttle body,when I took valve covers off last summer and cleaned sludge out.
Anyway I installed brand new gasket at last oil change (2700 miles ago).
Also checked front spark plugs since I had couple sludge up pretty bad during chemical therapy for sludge removal. They were fine, no sludge or excessive deposits, just some red/pink tan from gas additives. ( same plugs I had, Iridium NGK)
Couple hours ago I came to work and was waiting for gate to open, Codes p0150, p0153 pop up on scangauge. I think I seen them once before. Codes mean: 02 Sensor Circuit Malfunction (Bank 2 Sensor 1) and Oxygen Sensor Circuit Slow Response (Bank2, Sensor1).

Ok, so here is my thought. O2 sensors were swapped out about a year ago, with OEM sensors (don't remember which ones, Bosch/NGK/Dayco).
I downloaded Toyota TBS about sensors and figure out that bank 2 if near radiator.

For some reason I was sure it was opposite (possible advice from here).
So I was checking wrong spark plugs, since cyl 1 and 3 is in the back and I haven't seen them since summer. They were not bad, but I cleaned them anyway at that time.

So now it makes my life easier since I know that bank2 is front o2 sensor ( I have socket for it), probably will be able to change it myself.
What do you think guys: Should I first swap out spark plugs in the back or my o2 sensor? Should I stop using my MMO/TWC3 mix since it might foil stuff?
Car in my sig.

That is how front plug (cyl 2, first on the left) looked like about a year ago

that is how it looked last oil change:

 

[abycat]

 

[Chris Meutsch]

Yikers. You've got a previous sludge problem followed by a missing gasket along with fuel additives. You've done your proverbial best trying to clean it but it looks like a compound problem.

Not sure what the fix is at this point. I know that's no help.

 

[zyxelenator]

I think plugs are the case. Since it shows random misfires and lean code for same bank. O2 can throw codes if there is unburned fuel. I'll check for melted wires, since it it really close to headers.
Car drives and acts fine as usual.

 

[postjeeprcr]

Bank 2 would be right side not front. If there are 2 O2 sensors in the system on a side, Bank 2 sensor 1 would be front.

I also would think it would say rich if it was getting to much fuel and not burning all of the fuel. Lean is less fuel than desireable.

 

[zyxelenator]

engine is sideways. Page 3 LINK
Last page indicates front upper sensor. bank 2 sensor 1

 

[Dakota1820]

A lot of the time when you have a missfire it will throw a code for o2 sensor to lean because the car tries to compensate for the extra fuel and it actually causes a lean condition. I've seen it before.....not all the time but some....

 

[zyxelenator]

Got an actual CEL yesterday morning while idling in parking lot and entrring route to gps. Engine was alredy warm, after 20min drive. P0153 o2 sensor code. Checked wires when got home. They look brand new. Will see if any misfire alarm show up again. If not, probably falty oxygen sensor. I guess. No other alarms after first post in this thread.

 

[zyxelenator]

No alarms today, thru lots of idle on the run to get beer and some food from SNS. Car fully warmed up, ran about 2 miles total, and idle for about 20 min.That's my day off runs, leave near lots of shops and restaurants, so car is short tripper, avg of 3 days in a week.Rest is 17 miles one way run on hwy to work.
Any ideas about codes? i notices i shows more alarms when it is cold. It was warmed today.

 

[zyxelenator]

Took out O2 sensor today.Had some soot on it and slightly little pinkish tan, similar to spark plugs.Cleaned it,put little anti seize, put it back. Do they suppose to make clicking noise similar to PCV valve when you shake it? No alarms on the way back from garage.

 

[Vikas]

There are NO moving parts on an O2 sensor. It better not make any noise when you shake it.

Since you have the ScanGauge/UltraGauge, just monitor the voltage and/or fuel trim of that sensor.

 

[zyxelenator]

hmm, I'll watch for codes, it's gonna get cold soon again,they tend to show when cold. Will try to find voltage on scan gauge

 

[zyxelenator]

On the hwy drive home P0171 alarm chimed. System Too Lean (Bank 1).
I guess when spring comes I will search for air leaks,change 3 back plugs, and maybe top O2 sensor.
I just set up scan gauge to show voltage on all 3 O2 sensors. What I'm exactly looking for? They all showed different voltage on idle. It did raise if I rev a little bit. Do I look for constant/negative voltage?

 

[Vikas]

Voltage measurement is going to be pretty difficult. Set it up to watch the ST/LT fuel trims for both the banks. Also add MAF reading to the scanned PID list.

Do you get both P0171 and P0173 occasionally? If so, you need to look for something which is common to both the banks e.g. dirty or marginal MAF or airleak just before the split i.e. between the MAF and Y-point.

If you watch ST/LT fuel trims and two banks are widely apart, then the problems is limited to single bank. If both the LT are trending towards 20%, I would first clean MAF with CRC MAF sensor and if that did not fix, get an OEM one to replace it. But absolutely rule out any air leaks first.

- Vikas

 

[Vikas]

Since those era OBD-II does not have fast refresh rates, watching O2 voltage on circa 2000 model years is only good for post-cat O2 sensors. For primary (i.e. pre-cat) O2 sensors, the output changes faster than the OBD-II sample rate. But if you are monitoring the two primary voltages, at least you could see if one is sluggish as compared to other.

 

[zyxelenator]

Ok, I'll watch ST/LT fuel trims. And it is only P0171 that pops up no P0173.
I may have air leak, I will change something in my set up asap. But I made this change couple days ago, and codes where showing up before. I installed glass/metal (with metal mesh filter element) inline fuel filter to pcv hose that goes to air intake. Not sure that one old clamp holds it tight, will buy clamps with screws. That mini catch can works, already can see about dozen oil drops there.

 

[zyxelenator]

I think O2 sensor is faulty (clicking sound when shaking) + P0150+P0153+P0171 alarms today during shorts drives.
P0150 - 02 Sensor Circuit Malfunction (Bank 2 Sensor 1)+ Oxygen Sensor Circuit Slow Response (Bank2, Sensor1)+ System Too Lean (Bank 1)
http://www.obd-codes.com States that 02 Sensor voltages should be between 0.1 and 0.9. O.1 =0.9 rich. Scan gauge showed that upper sensor(B2 sensor 1) barely reaches 0.1 most time.

 

[zyxelenator]

Now question widch should I get:
Denso 234-4209 Universal Oxygen Sensor (Air and Fuel Ratio Sensor)
UNIVERSAL~CALIF - REAR~EXC CALIF - FRONT, REAR for $27.50 and work on wires.

Denso 234-4622 Oxygen Sensor (Air and Fuel Ratio Sensor)
EXC CALIF EQPD, FRONT - OE STYLE $62.60

Bosch 13354 Oxygen Sensor, OE Type Fitment
EXC CALIF EQPD, OE TYPE BEFORE CATALYST $56.94

NGK 24594 Oxygen Sensor - NGK/NTK Packaging
EXC CALIF EQPD, PRE-CAT $77.19

I lean towards NGK, since I respect Japanese quality and thay are OEM for Japan Camries.
Denso is OEM for KY made Camries.
Bosch is company whom first made and introduced O2 sensors in general.
Not sure which ones I have right now, but one of 3 brands above. They(2) were swapped little longer that a year ago.

 

[Vikas]

Denso or NGK; yours sounds lot cheaper than what I expected. I replaced mine (4-cyl) and it was over $100. Yours should also be the expensive type i.e. air/fuel ratio sensor than just O2 sensor. You car most likely is going to be CALIF EQPD; Japanese generally sell 50-state compliant vehicles in all states. Look under hood decal. If not sure, look at the connector and buy new one with the same connector rather than splicing a generic one there.

The Bank2 primary sensor obviously needs to be replaced. It is a mystery as to why you are getting Bank1 system too lean error though. But replace the broken O2 sensor first first.

Is Bank2 closer to radiator?

 

[zyxelenator]

Yes, bank 2 is closer to radiator, sensor is not far from oil filter. I also paid attention today(I haven't set up Shrt trims yet, 4 separate hwy drives for about 60 miles total) to LT fuel trims. Fuel trm 1 (long) is always twice less and most time goes to negative numbers. Trm 2 is twice more, and I've seen negative numbers ones there. Do they correspond to bank numbers ? If so, bank 1 has negative numbers(firewall side of engine) Or they should be like that(negative numbers instead of positive?). Fixing air leak (pcv pipe to intake) tomorrow.
P0171 light up CEL twice today.