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Bad MAF?

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Old 11-02-2011, 12:45 PM
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Default Bad MAF?

Not sure if this in the right section but Iv been getting bank 1 and 2 lean codes that have been going on randomly. I checked for vacuum leaks and found nothing. Today I cleaned the MAF with cleaner then the ses light turned off. The next time I went to start the car, it came back on when I was in my driveway so while it was running I unplugged it and it still ran as if i did nothing. Then I ended up taking it off completely and it still ran the same. Not sure if this is relevant or not but the car has a high number of miles and when I bought it the MAF was on backwards (Screen facing throttle body) with all sorts of crap in it. Is my Maf bad or should there be something else I should look for
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Old 11-02-2011, 01:04 PM
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Did you replace the MAF in it's normal position?
The MAF could be bad if someone messed with it.
Clean it, install back into engine and check it again.
Un plug your battery for a few minutes 1st.
Then see what happens.
If it corrects itself, your ok.
If not, time for a new MAF.
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Old 11-02-2011, 01:07 PM
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thanks, ya I put it in its normal position (screen facing lid)
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Old 11-02-2011, 02:21 PM
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Lean codes are more likely O2 sensors than MAF, although
an extra grimy one could bend you lean.
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Old 11-02-2011, 02:32 PM
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I actually changed the front o2s about a month ago which is when I got the same codes last so idk if that'd do it
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Old 11-03-2011, 08:34 AM
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How does the car run? If the MAF was bad, it would run rough. If it runs fine, many different sensors can cause the car to run lean. (This is going to be a tough one.)
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Old 11-03-2011, 01:12 PM
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The car ran real rough. i actually went out and got a reman MAF from autozone and the code went away.
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Old 11-03-2011, 01:55 PM
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I ran my mad backwards for a while without any ill effects, seems to just read air going past it regardless of position. Bad mad symptoms could be hard starts and running rough
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Old 11-03-2011, 10:19 PM
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Most likely a bad Maf.. highly doubt its the 02 sensors.. have you replaced your fuel filter??
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Old 11-03-2011, 10:46 PM
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Exhaust leaks before the front 02 can cause a false lean. Hear any ticking coming from the headers/manifolds?
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Old 11-04-2011, 12:09 AM
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Run a bottle of Lucas fuel injector cleaner through it.
One small bottle will clean out your system real nice.
If that doesn't help, it's gotta be a bad MAF.
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Old 11-04-2011, 12:38 AM
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I had Bank 1 and Bank 2 lean codes 2 months after putting in 2 new 02 sensors. One was a dud.......and it caused the other Bank to throw codes too.

Get a scan and see how the 02 sensors are switching.......one of mine showed 0-4, it was a dud. It caused the other to show lean, slow repsonse and low voltage CODES.

I put 2 new ones in tonight.....all better.

Moral of the story: One bad 02 sensor will cause the other one to throw false codes. Real codes, but false because the bad 02 sensor is messing up everything....

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Old 11-04-2011, 08:19 AM
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As common as they go bad on these cars, I'm surprised nobody has mentioned your intake gaskets possibly leaking. On a cold start you can spray some carb cleaner around the intake and see if your idle changes.

With these codes, it can be alot of things but the key is to figure it out as cheaply as possible. I would hold off on buying new o2's or a new MAF until you exhaust the free or cheaper options first.
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Old 11-04-2011, 09:57 AM
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Originally Posted by lt1pwr1 View Post
As common as they go bad on these cars, I'm surprised nobody has mentioned your intake gaskets possibly leaking. On a cold start you can spray some carb cleaner around the intake and see if your idle changes.

With these codes, it can be alot of things but the key is to figure it out as cheaply as possible. I would hold off on buying new o2's or a new MAF until you exhaust the free or cheaper options first.
True. Thats one of the things I tried before buying anything. It wasn't the gaskets on mine...BUT 5-6 years ago I replaced both head gaskets and ALL of the intake bolts had come a little loose, not bad, but they all turned a couple times to get them tight again.

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Old 11-06-2011, 07:43 PM
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Thanks guys I already got a new Maf and o2's, and yes, I recently changed the fuel filter. After the code went away I was able to borrow a scan tool and it popped up with a low voltage code, I forgot to write it down so idk the number.
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Old 11-06-2011, 10:06 PM
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Originally Posted by mjs1012 View Post
Thanks guys I already got a new Maf and o2's, and yes, I recently changed the fuel filter. After the code went away I was able to borrow a scan tool and it popped up with a low voltage code, I forgot to write it down so idk the number.
You probably just have a bad "NEW" 02 sensor.....like I just went through. One bad one will make the other Bank throw codes......as I said above. If one 02 sensor is showing anything wrong by way of a scan while the engine is running...change it.

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Old 11-07-2011, 10:51 AM
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ill check the o2s once I have the time. the ses light is off and I think i hear an exhaust leak so maybe thats what could be the cause.
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Old 11-07-2011, 01:10 PM
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I'd still scan it. There could be codes even if the MIL isn't on.
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Old 11-07-2011, 01:19 PM
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I did on Friday and the only other one that showed up was a low voltage code and I forgot to write it down
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Old 11-07-2011, 04:51 PM
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If you have an exhaust leak within like 10 inches AFTER the 02 sensor.......it will cause problems. The air in the exhaust tubes actually go back and forth in them......if it sucks air in and reaches the 02 sensor thats bad.

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