LS6427

iTrader: (2)

Couple months ago.......after my car sat for 4 months I had:

0131 0P2 Sensor Circuit Low Voltage (Bank I Sensor I)
P0151 02 Sensor Circuit Low Voltage (Bank 2 Sensor I)
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)

Car has been running perfect since I installed two new 02 sensors up front over 1 month ago. Rears have been tuned out for 9+ years.

So....a couple days ago I start my car, take off and its missing throughout the rpm range. After 3-4 minutes it goes away 100% and from that point on engine runs PERFECT. Normal gas mileage and all. I drove 2 hours home from Vero Beach Sunday night after it did this missing crap for about 3-4 minutes. Gas mileage was normal and engine ran great after it stopped missing all the way home on the highway.

It has this now:
P0131 0P2 Sensor Circuit Low Voltage (Bank I Sensor I)
P0151 02 Sensor Circuit Low Voltage (Bank 2 Sensor I)
P0153 02 Sensor Circuit Slow Response (Bank 2 Sensor 1)
P0443 Evaporative Emission Control System Purge Control Valve Circuit

I replaced that purge valve and cleared that code.

So, that P0153 is an additional code I did not have before.

How can an engine miss like crazy for JUST 3-4 minutes.........then all of a sudden...every time.....make the engine run perfect. If I turn the engine off for 5-10 minutes AFTER driving around, then start it back up it will miss again for that 3-4 minutes, then clear up. If I just turn it off for a few minutes I can start it back up and it will not miss.......it will just run normal.

Maybe that P0153, Bank 2 sensor is just a bad "new" sensor.
Can one bad 02 sensor cause this?

Whats up with this......................thanks.

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EricWS6

Do you just start the car and for the first few minutes it misfires? If it does misfire only after you first start it up, will it act the same if you shut the car off for 10 min and restart?

LS6427

iTrader: (2)

Yes. If I start it up it will sit there and idle in "Park" and instead of a normal 925 rpm smooth idle that I've had for 9 1/2 years....it will sit there and stumble around the 900 rpm mark.....just kind of slightly, not terrible. But clear stumbling missing.

Then if I back out and take off it will stumble (miss) for about 4 minutes......then like a light switch was turned on it will come alive and, smooth right out, and stay that way till its shut off again.

And its a certain time frame that will allow me to start it back up...AFTER it was running good......and not have immediate stumbling "missing". If it sits too long, maybe more than 10-15 minutes....I have to go through that stumbling "missing" time frame again till it clears up after that same 3-4 minutes.
If I shut it off...AFTER it was running good.....but I re-start it pretty quick, like within just a couple minutes, I can drive off and the stumbling "missing" is not there, it runs normal.

Its almost like I have a "timer gremlin" in my PCM that says......"I'm gonna make you run like **** for 3-4 minutes, then you can have full, smooth power."

I'll try to get a video a little later when I leave the house.

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Prorac1

iTrader: (4)

It could be your car going between open and closed loop, when its running bad than good. Deffinately a closed loop problem (cold mode, start up mode, etc). Eric L

LS6427

iTrader: (2)

Yea....but for 9 1/2 years with my 427ci.....I could start my engine and within 3 seconds when the engine and coolant is still COLD.....drive away and the engine performs perfectly smooth with zero issues.

Or if the engine has ever been totally hot and I shut it down, then a couple minutes later when its still totally hot....restart it and drive away perfectly normal.

It shouldn't matter what loop I'm in.......it should run perfectly either way.....right?

Or do you mean some other system or sensor that "closed loop" uses might be bad or failing?

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Prorac1

iTrader: (4)

Yes, I think this is an ECM function problem. You should take it to a tuner and have it scanned and checked out. Eric L

Prorac1

iTrader: (4)

Your ECM stays in "cold mode" for 3 to 5 min, or until a preset engine temp is reached. Eric L

LS6427

iTrader: (2)

Ok...so what would cause the stumbling "missing" all of a sudden now while in closed loop?

Its always run smooth and normal in closed loop (cold engine) before?

Could a failing Coolant Temp Sensor cause this missing?


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Prorac1

iTrader: (4)

check the voltage at the O2 sensors on both banks. Thats where id start. At least thats what its telling you. Eric L

LS6427

iTrader: (2)

OK.

question:
If the voltage is bad or wrong....why would it clear up after ~4 minutes and run great? Shouldn't it run like crap always, if there's a voltage issue?

.

LS6427

iTrader: (2)

Prorac1,

Since that new code 153 is Bank 2......should I swap it with the Bank 1 sensor and see if I get a code for the drivers side?

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ss454327

iTrader: (10)

That would be a very good place to start.

LS6427

iTrader: (2)

^^^^just swapped'em....gonna take a ride to the auto parts store to check the codes...........hope its just a bad 02 sensor.

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LS6427

iTrader: (2)

So....I got just these codes:

P0131 02 Sensor Circuit Low Voltage (Bank I Sensor I)

P0174 System too Lean (Bank 2)

Looks like it may have followed to "Bank 1" (P0131)
But I also have P0174, which said was "Pending".

***Can a bad 02 sensor on Bank 1 cause Bank 2 to run lean?

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pwrtrip75

iTrader: (8)

What is the batteries voltage when its running? What is the batteries voltage when its off? usually an intermittent problem is something electrical... 90% of most electrical problems are a loose or dirty connection. If main voltage is low it could affect random sensors... sometimes it affects one, sometimes several, sometimes none... Not often do multiple sensors go bad... usually when that happens it a power or ground issue causing the sensors to send a false signal to the pcm.

LS6427

iTrader: (2)

According to the gauge they are normal.....but I know thats not a great indicator for accuracy.

I did notice a few times in the past 6 months, at night, when I turned my lights on I would look closely at the gauge cluster, while idling, and it would be getting dim and bright, dim and bright, dim and bright.......continually. Like phasing in and out. Just a little dim, not much at all. But then sometimes it doesn't do it. I've never had electrical issues and I have no problems with playing my 1000 watt stereo with a 12" woofer at night with all lights on and a/c blasting.

How about post #14........I swapped the 02 sensors and the problem popped up on the Bank 1 side........

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pwrtrip75

iTrader: (8)

The motor mounts were stock on my car and when I floored it the engine would torque over and the header hit a wire once in awhile. Car would shut off, pop, sputter, and I went through like 3 alternators before I figured it out. Of course doing so it set all sorts of random codes also...none which were legit, just a result of shorting a wire out.

LS6427

iTrader: (2)

I'll check'em. But its just strange that after the 4 minutes....everything is great. No matter how I drive, normal or aggressive. I would think if a wire was frayed or shorting, I would always have this issue.

Does the PCM revert to a SD "default" tune if the 02 sensors are bad.......?

.

LS6427

iTrader: (2)

Listen to this now.........

I start the engine today, and drive off immediately, expecting it to miss/stumble for its 3-4 minutes. NOT TODAY. This time it ran PERFECT for about 2 minutes and 1 mile of distance. As I was cruising steady down the road at 45mph...it came back and started missing/stumbling. THEN it stopped after about 2 minutes and was fine for the next 10 minutes to the auto parts store.
lol....WTF!!!!!


NOTE**** P0131 02 Sensor Circuit Low Voltage (Bank I Sensor I)....was there last night after I swapped the 02 sensors. Now its gone.......

These are the only two codes there now....only Bank 2 codes:

P0151 02 Sensor Circuit Low Voltage (Bank 2 Sensor I)
P0174 System too Lean (Bank 2)

Can two new 02 sensors I installed a little over 1 month ago be bad..........??

Other than 02 sensors wigging out....what causes "lean" conditions or voltage problems to 02 sensors?
Crank Shaft sensor?
Camshaft sensor?
TPS?
IAT?
MAP?

(and whatever it is....its intermittent.........runs bad, runs good.......

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edcmat-l1

iTrader: (10)

I would bet it's too lean when you first start it, and after it runs for a bit, it goes into closed loop, adds a bunch of fuel and BAM starts running good once it has enough fuel.

Then, even once it's warmed and in closed loop, and running good, your fuel trims are maxed. When your fuel trims are maxed, alot of times they'll reset to zero, and start over. That's your intermittent rough running even when it's warm.

The fuel trims being maxed are part of the lean code.

Root cause will be the tune is off pretty bad, or a contaminated MAF sensor.

PS, you need to check you plugs and plug wires real good too.