msbmustang Posted January 24, 2014 Report Share Posted January 24, 2014 P0171 Error Code-I just did a forum search and did not find anything on this? I must be doing an incorrect search because I believe this has to have come up before? I found online that P0171 it is a "Lean" condition and it might be due to a dirty MAF or an air leak. Since my GT500 has 135K miles now a dirty MAF seems logical. Does anyone have any thoughts on this? Is it easy to remove and clean the MAF? Also if I remove the tune from Justin (more power/better gas mileage) the problem goes away! Thanks Everyone, MSB Mustang / Mark Link to comment Share on other sites More sharing options...
grsybtch Posted January 24, 2014 Report Share Posted January 24, 2014 This is from an auto repair database specific to a 2007 GT500Hope it helps! DTC Code P0171 DTC Code: P0171 Description: Bank 1 System Too Lean Probable Causes: Wire harness - Check harness for correct voltage, open, short to ground or short to voltage Fuel pressure - Pump, regulator, filter or lines Exhaust leaks or restrictions Vacuum leaks, damaged hoses or improper routing Fuel contamination Sensor not properly installed Link to comment Share on other sites More sharing options...
msbmustang Posted January 24, 2014 Author Report Share Posted January 24, 2014 I think it might be a dirty MAF but I am not sure how to clean it or even get to it? Has anyone cleaned one before? Thanks, Mark/ MSB Mustang Link to comment Share on other sites More sharing options...
twobjshelbys Posted January 24, 2014 Report Share Posted January 24, 2014 I think we went through this once before, if not here then on another forum. There is a MAF cleaning kit you can get from one of the car parts places, I think it was CarQuest, but check the others. But it was reported the part is fairly fragile, and cost of a replacement isn't that much, plus you risk you'll pay for the cleaning kit and have to get a replacement anyway. I don't think they are extremely special parts and you could probably get one from CarQuest or the others for much less than Ford. Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted January 24, 2014 Report Share Posted January 24, 2014 I think it might be a dirty MAF but I am not sure how to clean it or even get to it? Has anyone cleaned one before? Thanks, Mark/ MSB Mustang The MAF housing is where the PCM harness plugs into the area just downstream from the air filter. Two hose clamps and you have it in your hand. The MAF sensor screws into the housing with two torx screws. There is a cleaner specifically for MAF sensors, should be able to find it at NAPA or any other good auto parts store. If you can remove the MAF sensor from the housing, just spray it with the cleaner and let it dry. Otherwise, pull the housing, pull the sensor, spray/clean, allow to dry and reinstall. Pretty easy but I don't know why a MAF would only show lean on ONE bank. I suspect something else. Phill Link to comment Share on other sites More sharing options...
twobjshelbys Posted January 24, 2014 Report Share Posted January 24, 2014 You mentioned a new tune. When you install the new tune did you drive it through the learning cycle? When I got my GT it threw a similar code. It was easy clear the code and let it go through the learning cycle. I would suggest you clear the code then disconnect the battery for a couple of hours, then connect the battery again, and go through the "learning" process outlined in the "new battery" section. It requires you to get the engine to operating temperature and do a few sustained idles (with and without the A/C on) and then drive it for a number of miles. If the code returns then suspect a failing part. You might want to contact the supplier of the tune to assist you. Link to comment Share on other sites More sharing options...
msbmustang Posted January 25, 2014 Author Report Share Posted January 25, 2014 I went out and bought a can of CRC MAF cleaner at ORiley's. Sprayed it 15 times into the slot on the side and through the smaller slot in the top of the housing to clean the two sensors, that look like 1/8 W resistors. I then let it dry for a couple of minutes and put the MAF assembly back into the air cleaner housing.. WOW! Problem solved! The car idles, launches, and runs better now. Should have done this multiple times before I hit 135K miles! I have always had a little shudder on launch and that is almost totally gone now. I would recommend cleaning the MAF every time you change your air filter! Best thing I have ever done to my GT500... for $8! MSB Mustang / Mark Link to comment Share on other sites More sharing options...
msbmustang Posted February 13, 2014 Author Report Share Posted February 13, 2014 Got the P0171 error again after putting in a tank full of Costco Premium 91 oct gas so it was not just a dirty MAF. (The MAF was really dirty though so it was good to clean it!) I took out the Justin gas saving tune and used the tune that came with the SCT for the 2007 GT500 (it displays "GT" in the programmer display but I verified several years ago with SCT that it really was for the GT500 and the unit says GT500 right on it). No P0171 error all the way to Sacramento and back to HMB. 1st week of a new part time contract audio Job. Yeah!) So it appears something has changed (wore out) with the engine. Either that or the Costco Premium gas has gotten worse lately (lower octane...Or the engine is starting to have a problem at 135K miles now? For now I will just use the the higher HP tune that came with the SCT programmer. On a side note: The owner of the new company I am working for now has a Porsche Cayenne turbo and we rode around in it yesterday. 295 tires all the way around and 0-60 in 4.4 sec! He says we should go out to the track together sometime! Maybe my tune and one piece driveshaft with give me the few extra .1secs I need to make the difference It would suck being beat in the 1/4 mile by a SUV! Mark / MSB Mustang Link to comment Share on other sites More sharing options...
msbmustang Posted March 25, 2014 Author Report Share Posted March 25, 2014 Replaced the fuel filter (see other thread on creased plastic fuel line) and the error returned but not until I filled up at Costco. Been using Costco premium gas for 5+ years without any problems, but I do add a 1/2 of a can of ORiley's octane booster with every fill-up. After the error returned (after the fill-up) I took out the higher HP/better mileage tune from Justin at VMP and the problem went away again? Funny that if the gas level goes down a bit I seem to be able to reinstall the tune and have no problems until the next fill-up at Costco? Been using that tune for 5 years without a problem. I switched to the standard increased HP tune that came with the SCT X-3 and that works fine (even with a fill-up) but gets about 1-2 mpg less than the tune from Justin used to get. I guess I will just use the tune that came with the SCT X3 for now. Note: The stock Ford tune works fine also. MSB Mustang / Mark Link to comment Share on other sites More sharing options...
revan Posted April 3, 2014 Report Share Posted April 3, 2014 Wow, what a crazy set of issues. Wish I had answers for ya, but I will say that if you're using an oil based air filter (such as the K&N filters), those are known to leak small amounts of oil onto the MAF sensor and over time it will mess with the signal. You've eliminated that possibility by cleaning the MAF sensor, but if you're using an oil based filter you'll probably have to clean it again, more often than every 135K miles The only other thing I can think of is to check all your hoses on the intake tract and make sure the blower inlet bolts are torqued down. Justin @ VMP has said many times that 95% of the issues they get with Lean error codes are a result of vacuum leaks due to hoses not being properly connected or loose bolts on the inlet or the blower itself. Good luck! Link to comment Share on other sites More sharing options...
hotrodjohn71 Posted January 8, 2017 Report Share Posted January 8, 2017 Msbmustang, I am curious to know if you ever found a solution to those codes.I've been chasing P0171 and P0174 for what seem like years. After one trip to an independent shop, another trip to Ford, changing fuel pump MAF sensor fuel filter, professionally cleaning injectors. Never finding any kind of vac leak, no change. My problem and manifests only when the car is good and hot yand has been shut off or 20 minutes or so, like when running into a store. Upon startup it will stumble and sometimes die but usually correct itself in about 8 seconds. Link to comment Share on other sites More sharing options...
Secondo Posted January 8, 2017 Report Share Posted January 8, 2017 Had the same codes on my driver car, a '97 V8 T-Bird. It was the oxygen sensors. Replaced them, running great now over 2 years, no issues or codes. Link to comment Share on other sites More sharing options...
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