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Discussion Starter #1 (Edited)
Ok this is a two parter here....My check engine light turned on a few weeks ago. I went to the shop and got the code read and it was the dreadful P0171 and P0174 codes. For those of you who do not know what it means, it is Bank 1 and 2 Systems to lean.
To make a very long story short, I have done EVERYTHING UNDER THE SUN to try and fix it...I have inspected ever hose, replaced any and every one that had the slightest bit of dry rot on them...I tried cleaning the MAF sensor and then resetting the ECU...Nothing...Then the other day I sucked it up and bought a new MAF sensor and reset the ECU...this morning, same codes pop back up again. PLEASE HELPPP!!
I also have every intake hose and screw/bolt tightened to factory specs
GOING CRAZYYYYY!! Any Ideas??

Also, second question is that when I went to replace the MAF sensor, the piece of S**T warranty company claimed that the MAF sensor is not part of the fuel injecting system, but is part of the emissions category which is not covered under my aftermarket warranty...is that true?
 

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Discussion Starter #2
Note: I also thought the repacement MAF sensor was bad, so I returned it and got a new one with the same results!
 

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Discussion Starter #4 (Edited)
MAF isn't part of the fuel system.
Would you say it falls under the emissions category? Because I though that the job of the MAF was to tell the ECM how much air is going into the engine so it knows when to ignite/how much fuel to spray etc.

Most importantly...any help with the first part would be much appreciated...I'm at the end of my rope here
 

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Unfortunately, it could be alot of things.

-Misfire
-Both Precat o2 sensor malfunction
-Exhaust leak
-MAF/IAT malfunction (you already did this)
-Fuel filter clogged or fuel pump malfunction
-Fuel leak from fuel delivery pipe and fuel pump
-Pressure regulator malfunction
-Fuel return hose clogged
-Fuel injector malfunction
-VVT malfunction
-Insufficient compression
-PCM malfunction
-Intake air leak (you did this already)
 

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Discussion Starter #6 (Edited)
Unfortunately, it could be alot of things.

-Misfire
-Both Precat o2 sensor malfunction
-Exhaust leak
-MAF/IAT malfunction (you already did this)
-Fuel filter clogged or fuel pump malfunction
-Fuel leak from fuel delivery pipe and fuel pump
-Pressure regulator malfunction
-Fuel return hose clogged
-Fuel injector malfunction
-VVT malfunction
-Insufficient compression
-PCM malfunction
-Intake air leak (you did this already)
okay so how does one go about doing that?
I dread bringing it to the dealer but have come up short with a regular shop
Oh, I also forgot to mention I had a professional fuel injector system cleaning and inspection, which started this mess, and it read a misfire code so I doubt its that
 

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Has anybody had the EGR valve or manifold off during this mess? Another member had some work done and the shop forgot to reinstall the stainless steel EGR gasket/restrictor when they put the manifold back on which caused the same trouble.
 

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Does your car have any mods such as a cold air intake?
 

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I had a professional fuel injector system cleaning and inspection, which started this mess, and it read a misfire code so I doubt its that

Wait a minute. These problems showed up AFTER you took it to someone for a fuel injector cleaning? Did you have any problems before that? Is everything on your engine absolutely stock? Intake, MAF, plugs, coils, etc.?

Does it idle like crap? Like others said, it sounds like you are getting unmetered air in the system. Have you inspected the intake manifold gasket? If they took it off, they may have tightened it too much and cracked something. Or maybe the fuel rail isn't tight and air is getting past the injectors.

What exactly did the fuel injector cleaning involve? I'd go to whoever did the cleaning and grill the crap out of them. Find out EXACTLY what their procedure is. Also, get the branch manager's name. They have cost you a bunch of money.

HTH,
BP
 

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Discussion Starter #11
EVERYTHING IS STOCK!
I got a fuel injector cleaning because I had an engine misfire code before I got it done...The intake manifold was taken off to put the back spark plugs in, but I also purchased an intake manifold gasket set with all of the rubber gaskets, and the mechanic working on the car tested them all. Before the cleaning, the car idled fine, but drove terribly. When I accelerated, it bucked like nuts. The cleaning consisted of putting a normal fuel injector cleaner into the car, then putting some other sort of cleaner directly into the engine which supposedly helps flush out the carbon residue buildup on the injectors...it actually did work and that issue went away, but the check engine light stayed.
The guy who did the work is a really honest guy, and only charged $250 for labor to do the injector cleaning (suppose to cost about $100 on its own), putting in all the plugs, and he did my front breaks, rotors and calipers...which I was quoted wayyy wayy more from the dealer.

It does not idle badly at all...stays around 750rpm's and doesnt deviate more than 20rpm's sitting idle.
 

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Discussion Starter #12
Wait a minute. These problems showed up AFTER you took it to someone for a fuel injector cleaning? Did you have any problems before that? Is everything on your engine absolutely stock? Intake, MAF, plugs, coils, etc.?

Does it idle like crap? Like others said, it sounds like you are getting unmetered air in the system. Have you inspected the intake manifold gasket? If they took it off, they may have tightened it too much and cracked something. Or maybe the fuel rail isn't tight and air is getting past the injectors.

What exactly did the fuel injector cleaning involve? I'd go to whoever did the cleaning and grill the crap out of them. Find out EXACTLY what their procedure is. Also, get the branch manager's name. They have cost you a bunch of money.

HTH,
BP

EVERYTHING IS STOCK!
I got a fuel injector cleaning because I had an engine misfire code before I got it done...The intake manifold was taken off to put the back spark plugs in, but I also purchased an intake manifold gasket set with all of the rubber gaskets, and the mechanic working on the car tested them all. Before the cleaning, the car idled fine, but drove terribly. When I accelerated, it bucked like nuts. The cleaning consisted of putting a normal fuel injector cleaner into the car, then putting some other sort of cleaner directly into the engine which supposedly helps flush out the carbon residue buildup on the injectors...it actually did work and that issue went away, but the check engine light stayed.
The guy who did the work is a really honest guy, and only charged $250 for labor to do the injector cleaning (suppose to cost about $100 on its own), putting in all the plugs, and he did my front breaks, rotors and calipers...which I was quoted wayyy wayy more from the dealer.

It does not idle badly at all...stays around 750rpm's and doesnt deviate more than 20rpm's sitting idle.
 

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Did you check for the EGR gaskets?
 

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Discussion Starter #14
Did you check for the EGR gaskets?
Would the EGR have to be seperated in order to take off the intake manifold? I feel like if that was the case, when I bought the intake manifold gasket set, it would probably have came with it right?
 

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Would the EGR have to be seperated in order to take off the intake manifold? I feel like if that was the case, when I bought the intake manifold gasket set, it would probably have came with it right?
Yes, it would need to be separated, but the are 2 ways to do it. I doubt this would come with your set. To check if it is there look for the brass rivet by my finger in the first picture. The second picture is what it actually looks. If it is not there the opening thru the EGR line is the size of the large black circle instead of the small hole through the middle.
 

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Discussion Starter #16
Yes, it would need to be separated, but the are 2 ways to do it. I doubt this would come with your set. To check if it is there look for the brass rivet by my finger in the first picture. The second picture is what it actually looks. If it is not there the opening thru the EGR line is the size of the large black circle instead of the small hole through the middle.
Thanks a lot...I'll check once it's light out in the morning.
 

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not a V6 guy, so take it for what it's worth.

but, sometimes as you clean the fuel system out, when that crap goes downstream it makes shit on the O2 sensor/s. they don't get a great reading, says the car is running lean...maybe? you could take a look at them, though i'm not sure if that will always tell the issue. maybe you can find another local V6 owner willing to let you swap and see if that helps your issue before dropping cash on them?
 

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Discussion Starter #18
not a V6 guy, so take it for what it's worth.

but, sometimes as you clean the fuel system out, when that crap goes downstream it makes shit on the O2 sensor/s. they don't get a great reading, says the car is running lean...maybe? you could take a look at them, though i'm not sure if that will always tell the issue. maybe you can find another local V6 owner willing to let you swap and see if that helps your issue before dropping cash on them?
Ya I actually did that with the MAF sensor, and bought a new one which thankfully I was able to return when I learned that wasn't the issue. I believe if the issue is at the o2 sensor, that it will run a different code saying there is an issue on that end of it. I do know one of the things thats done with the Fuel Injector cleaning is some sort of hose is run up the tailpipe with a vacuum of sorts on the end, and its used to help increase the flow to avoid issues like that. I could be talking out of my ass on that one though.
 

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I suggest you get a workshop manual. It explains in what steps to troublehshoot and how to inspect certain parts on the car.
 

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okay so how does one go about doing that?
I dread bringing it to the dealer but have come up short with a regular shop
Oh, I also forgot to mention I had a professional fuel injector system cleaning and inspection, which started this mess, and it read a misfire code so I doubt its that
Some fuel system cleaners can do more harm than good, i used a cleaner once and it caused my plugs to turn all brown, causing the car to run like crap, check your plugs, couldnt hurt.
 
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