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P0171 O2 sensor persistent

2002 slt 4.7 magnum

I got a P0171 & eventually P0133 within days, took him in, got a new O2 sensor, no symptoms for 24h, then exhaust started leaking into cabin again, white exhaust… took back, they found a small crack in something my husband forgets what, they sealed that… no symptoms for 48hrs…
Then the engine light returns, symptoms return- P0171 only, took it somewhere else, they replaced both O2 sensors, looked over rest of car found (don’t judge) a corroded spark plug they couldn’t even remove. Got it out addy the dealership, all good, clean bill of health for another couple days, but now back to P0171 code, exhaust in the cabin, white smoke, if idle long enough, it’ll be black when I take off…
Why is this persisting? How can I make it fixed?

It sounds like you have an air/fuel mixture problem. Exhaust leak, vacuum leak, something like that. Modern engines have to be air tight from the air filter all the way to the end of the exhaust pipe.

Better get that checked out again and permanently fixed

Would a leak show symptoms off and on like that?

I’ll call the shop and ask what they found on Monday

Possibly, depends on where the leak is. I would be more concerned about your health. Leaking exhaust into the cab can kill you before you know it.

It’s not an “off and on”. They never fixed the problem in the first place.

After replacing the O2 sensor and erasing the error code, it takes a drive cycle before the computer decides that all is well. To simplify, the cycle is not measured in time but by the miles you drive. I don’t know what the drive cycle is for your car. If for example it is 50 miles and you drive 50 miles in one day the computer turns on the error code in one day, if there is a problem. If you drive 50 miles over a 2 days period the computer turns the error code on within 48 hours.

The O2 code may or may not be related to the symptoms you describe but exhaust gas leaking into the cabin is a serious problem and needs to be addressed. Take it back to the dealer or a independent you can trust and have them figure it out. You don’t want to be driving around breathing exhaust fumes.
Also you say you can see the the smoke and its white…That sounds like oil burning off of the exhaust manifold… make sure to have that looked at as well. Burning oil has a very distinctive smell …Acrid… coolant on the other hand has a sweet smell but can also produce white smoke so have your coolant system looked at as well.
Good luck.

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I have noticed a few of the older 4.7 L Durango/Dakota trucks that smoke when accelerating away from a traffic light, I believe the valve guide seals need to be replaced. How does the exhaust get from the tailpipe to the cabin? Are you driving backwards?

Fault P0171 indicates a lean condition has occurred, the freeze frame data in the computer should be reviewed to know where to begin, it will show if the condition occurred at idle, while accelerating, at cruise etc.

Many P0171 faults that I dealt with in the past were caused by E85 in a non flex fuel vehicle but it seems that E85 is not sold in many gas stations today.

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