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2011 Forte SX 2.4L (thankfully MPI) A/T 144K miles
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I haven't found any vacuum leaks yet, but I was thinking, because the engine uses a MAP instead of a MAF, would a vacuum leak even matter? ....
Yes, a vacuum leak would always be a problem. I understand the frustration with trying to chase these things down, and hopefully the shop can find whatever the issue is without a lot of expensive diagnostic time.
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #22 ·
Update: Got the car back, shop deep cleaned the fuel injectors and installed new spark plugs. Basically a little more than a tune-up. Hopefully this stays away for a while. I'll probably do an injector cleaner additive every so often to try and keep them from getting dirty in the first place. I also think a new fuel filter couldn't hurt, I'm sure it's dirty after 100k. Total cost was $400, $50 for the plugs, $90 for a fuel induction service, and $150 for the injector service, and $75 labor. They didn't find any vacuum leaks or anything else wrong with it.

Idle is now super smooth, and it seems to be running much smoother overall.
 

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First and foremost, I was glad to read your vehicle is running well now. That's always the goal and bottom line here, regardless of the why and the how. That said, and not wanting to sound like the turd in the punchbowl, I have a really hard time understanding what this 'deep' injector cleaning was all about.

It's a LOT of work to remove GDI injectors and clean them, and they could not have done all of that work for the price you paid for the cleaning. So without removing the injectors, I don't understand what else they could have done, because the injectors can't be soaked or otherwise manually cleaned while installed. So the only other possibility is to send Techron or some other cleaning agent through them, during regular running of the engine, just as you did with the Seafoam. And I have nothing whatsoever against adding fuel system cleaner to the gas periodically - I do this myself and always recommend it to others as well. So IMO the the only deep soak in this case was to your wallet, but no big deal because the total amount you paid for everything was not off the charts.

Now I will say that if the spark plugs were not in good shape, then changing them could certainly have made quite a bit of difference in performance. Guess there's no way to know for sure about that one. Anyway, again glad your vehicle is running well and the problem is resolved!
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #24 ·
First and foremost, I was glad to read your vehicle is running well now. That's always the goal and bottom line here, regardless of the why and the how. That said, and not wanting to sound like the turd in the punchbowl, I have a really hard time understanding what this 'deep' injector cleaning was all about.

It's a LOT of work to remove GDI injectors and clean them, and they could not have done all of that work for the price you paid for the cleaning. So without removing the injectors, I don't understand what else they could have done, because the injectors can't be soaked or otherwise manually cleaned while installed. So the only other possibility is to send Techron or some other cleaning agent through them, during regular running of the engine, just as you did with the Seafoam. And I have nothing whatsoever against adding fuel system cleaner to the gas periodically - I do this myself and always recommend it to others as well. So IMO the the only deep soak in this case was to your wallet, but no big deal because the total amount you paid for everything was not off the charts.

Now I will say that if the spark plugs were not in good shape, then changing them could certainly have made quite a bit of difference in performance. Guess there's no way to know for sure about that one. Anyway, again glad your vehicle is running well and the problem is resolved!
Well, when you're right, you're right. The code came back not more than 2 days after getting it back. Behaving exactly like it did before taking it in. Any details on how to physically remove the injectors on the GDI? I know they're deep in there. Now considering fixing it, getting rid of it and getting a non GDI car at this point 😂 I'll go back to ported injection.
 

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I don't have a manual for your vehicle, so I can't give you any specifics, other than it's likely to be a big job. However, one thing you need to consider is that this is the second time the vehicle was 'fixed' for an extended period of time. And IMO that just doesn't fit in with defective or clogged injectors.

One common thing about each time it ran well for a while was that a cleaning agent was added to the gas, which may very well be an important clue to what the actual problem is. And it makes me wonder if there is some issue with the fuel, tank, or even the evap system going on. You might want to try adding a bottle of Heet to the gas, to see if a specialty additive like that has a similar effect of clearing up the problem for another short/medium period of time.
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #26 ·
I was starting to think maybe it's not injectors as well... I know they used a BG fuel injection system cleaner, so at the very least any carbon deposits or buildup should be gone. They didn't use a fuel additive from what I understand, and the issue came back within less than 2 days, vs the week or more we'd get when using a fuel additive.

I wonder if it's an O2 sensor?
 

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... They didn't use a fuel additive from what I understand, and the issue came back within less than 2 days, vs the week or more we'd get when using a fuel additive. ....
The fuel system cleaning products are similar to the additives with respect to being able to 'dry out' water from the fuel, if it's actually present. So the fact that the BG fixed the problem for at least some period of time is what causes me to wonder about the quality of the fuel. Not at all saying I'm sure it's the problem, only that some of the prior results would fit in with a fuel quality issue. And that's the reason I'd want to try something like Heet, which is specifically designed to address bad fuel.

.... I wonder if it's an O2 sensor?
Yes, a malfunctioning upstream O2 sensor could also be the cause of your vehicle's issue. You could try the very simple test of unplugging that sensor, and try driving it that way to see what happens. Driving with that sensor unplugged will force the vehicle to remain in open loop, and use the preprogrammed default values for fuel management. A code will also be set, but that's not a problem, and the vehicle should be able to run just fine in open loop, using the fuel management dafaults (not quite as good as running in closed loop, but at least ok).

So if running this way for an extended period of time results in no longer having a performance problem, then that would make the O2 sensor the prime suspect. But if OTOH, if it immediately or fairly quickly starts to run poorly again, then I'd be back to trying to figure out if the issue is somehow related to the quality of the fuel.
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #28 ·
Yeah just tried unplugging the upstream O2 and it immediately ran significantly worse, the idle got even more rough than it was, almost like a surging. Think I might try Heet and see what happens with that.
 

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Yeah just tried unplugging the upstream O2 and it immediately ran significantly worse, the idle got even more rough than it was, almost like a surging. ...
And that would lead one to believe that the O2 sensor is doing a great job of compensating for whatever the actual problem is, by adjusting the fuel ratio in closed loop.

I'll add that having bad fuel is very uncommon these days, which is why I wouldn't push it as the likely suspect. But OTOH the symptoms do fit with bad fuel to some extent, and it also wouldn't be a really difficult thing to diagnose, so I guess why not follow up on it a bit.

And along with all of the other possible causes for the problem with your vehicle, I still wouldn't give up yet on a hard-to-find vacuum leak either.
 

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2013 Kia Sportage SX-T GDI
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Hey everyone, figured I would attempt to get some insight before doing anything to the car. I have a 2015 Kia Soul 1.6L with just under 100k miles. Had a P2191 code come up for a lean condition under load. Took it to the dealer and they said all the injectors were fouled and they wanted to replace all of them.

Thought how could that have happened, and tried SeaFoam to clean the injectors. It worked, and the car ran great for a little more than a week without any codes at all. Recently the code came back, and the engine runs noticeably rougher than usual.

I'm thinking there's a lack of fuel pressure under load, as it's on the original fuel pump and filter. More just curious if anyone has heard of this before and if I'm going in the right direction. The only other code on it is a C1555, and a P050A code popped up yesterday morning but it was in the low 30s in Florida so I don't think that one's related.

Any help would be appreciated, thanks!
I have 2013 kia sportage SX-T. I have same issue. P2191. I have switched out up and downstream O2 sensors, PCV valve, fuel pressure sensor, high pressure fuel pump, MAP sensor. I have done many different fuel additives, cleaners etc. I am so fed up with this code it's not funny anymore. You Tube doesn't have anything on it I guess cause its a pretty general code. I became tired of paying outrageous labor and parts fees a long time ago and do all maintenance and repairs on my vehicles. If I ever figure it out I'll let you know. Please let me know if you ever do. Thanks.
 

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Well, when you're right, you're right. The code came back not more than 2 days after getting it back. Behaving exactly like it did before taking it in. Any details on how to physically remove the injectors on the GDI? I know they're deep in there. Now considering fixing it, getting rid of it and getting a non GDI car at this point 😂 I'll go back to ported injection.
The injectors are located under the air intake manifold so you have to remove that. That is a big job though but thats the only way to access the injectors and the fuel rail pressure sensor which I did not long ago to my car. You will need a new gasket for the manifold if you decide to remove it. I run nothing but high octane in my car and periodically use cleaners and have done so since I bought it so I know my P2191 code is not from faulty injectors. I could be wrong though since I haven't replaced them yet. At $250 a pop times 4. That will be the last thing I try. Let me know if you fix.
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #32 ·
The injectors are located under the air intake manifold so you have to remove that. That is a big job though but thats the only way to access the injectors and the fuel rail pressure sensor which I did not long ago to my car. You will need a new gasket for the manifold if you decide to remove it. I run nothing but high octane in my car and periodically use cleaners and have done so since I bought it so I know my P2191 code is not from faulty injectors. I could be wrong though since I haven't replaced them yet. At $250 a pop times 4. That will be the last thing I try. Let me know if you fix.
Very interesting information. I had considered the PCV as well, but I tested it according to the service manual since it's easy to get to, and it's working just fine. I agree that I think it's a very general code. And to this day I have no idea how the dealership thought it was bad injectors, especially without pulling them. I think kiaguy002 is right that they were most likely guessing. The only out of line thing I noticed when checking all the sensors was the long term fuel trim. It doesn't ever change, and according to him it definitely should be. But why it's not, I don't know. The car hasn't gotten any better or worse, but obviously something's up, I just haven't had the time to really look at it. Can't believe you changed all that stuff and it got you nowhere. I'm definitely the type to know for sure that it's failed before replacing but I get it. How long have you had the issue and do you get the rough idle as well? Under load the car seems to run just fine. It's been serviced by the dealer the entire time it's been under warranty, this is the very first issue with it.
 

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Discussion Starter · #33 ·
So I did some research, and I'm going to try spraying some starter fluid into the intake tomorrow and see if my long term fuel trim drops. 40% is way way too high, and it's the only value that seems off. Now I can only seem to read one of the O2 sensors with my scan tool, but the one I could read was about mid-range, so that was at least good. If my LTFT doesn't change with starter fluid in the intake I'll start to investigate air issues like the other O2 I can't read, but if my LTFT goes back in line, it could actually be injectors... I know my fuel pressure is fine, but I don't know if that pressure is actually getting to the combustion chamber or not. If it's injectors, I might get another manifold gasket and attempt cleaning them manually.
 

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2015 Kia Soul 1.6L V4 2WD GDI
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Discussion Starter · #34 ·
Update, I was able to read both O2 sensors on my scan tool, instead of just the upstream. Upstream was cycling as normal, however the downstream was reading a constant 0.17 and not changing at all. I turned off the engine and unplugged it, and now the engine is running smooth and the LTFT finally goes down to 0 when under any load. It'll still go high (around 40%) at idle, but if that isn't normal it may be because of the lack of that sensor. But even at idle the engine isn't visibly moving around or running rough.

I checked both O2 heater's continuity according to the service manual, and both are within spec. Don't think I can easily test the voltage coming out of the downstream O2 because apparently it needs power in to send power back.
 

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2013 Kia Sportage SX-T GDI
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In my opinion I just don't think that injectors will cause this code to pop up. Remember that it is a lean code. Lean is too much air and rich is too much gas. I don't know about your car but mine is not exactly running to its max fuel efficiency. This tells me that the computer is injecting more fuel to compensate for the unmetered air or extra air its getting. Unmetered meaning that its somewhere after the MAP sensor and after my Turbo sensor. I personally have replaced both O2 sensors already and the high pressure fuel pressure pump. I still get P2191. I've even replaced the filter in the fuel pump in the tank and the fuel pressure regulator in there too. Very frustrating.
 

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I'd be checking the vacuum readings with a mechanical gauge if either of these vehicles were mine.
 
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