- Thread starter
- #21
Thanks for the input sir! May I ask if you had the lights go away during higher speed driving with more consistent RPMs? If a fuel pump were weak I think more load on it would only make the situation worse. Thanks!
P0171 and P0174 saga, intermittent on 2006 GX (3 Viewers)
- Thread starter CarGuyCarl
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No they only went away when I cleared code. I had a hesitation on accelerate starting at around 2k rpm. Thought I had bad plugs. Just a little flutter. Cruising straight you wouldn't notice or under hard accelerate, over 3k rpm. Maybe you can get mechaninc to pressure test, I'm not sure how they do it. But my guy forgot to hook up the filler neck when the tank was reinstalled. That was a adventure when I went to fill up.
- Thread starter
- #23
Thanks for your input sir! I think I will move forward with a fuel pressure test at some point in the next few days!
Zjohnsonua
SILVER Star
Don't get lost in the weeds.
You're looking for a change in STFTs that you control. How much change you see will be related to a ton of variables (what chemical you use, how large the leak is, how close you are to the leak when you spray...it goes on).
Toyota ECM's as a rule of thumb, do not like any changes to the intake system. that are not co-engineered with TRD (not sure exactly why). In my experience, whenever you are getting a P0171/174, and have an aftermarket intake,, well...it's the intake. They have a set amount of air that the computer wants to see coming in, and expects to come in, based off it's AFR maps that they put into the ECM from the factory. Your truck runs just fine, and it will. The issue isn't that it isn't running right. It's that the computer expects "X" amount of air at a given load, RPM, etc. And instead of the expected mass of air (MAF), it finds out that it has "Y" airflow, after reading the AF sensors, and it is also confirmed in the post-cat 02 sensors that "Y" much air has gone through the engine. Some will never give issues (as you can see from the previous responses), but if yours does, you're better off going back to the stock intake than trying to undo what Toyota has engineered into the system. It's all about emissions, and even though the ECM can compensate for the extra air, as you can see, it doesn't like to compensate. All the P0171 or 174 code is saying is that the ECM is seeing more air (unaccounted for oxygen) that it expected. Well, the point of an intake is to increase...airflow. You can keep on chasing the ghost, or you can just go back to stock. You haven't done anything wrong per se by putting on the intake, some ECM's or setups are just more finnicky to aftermarket stuff. Hope this helps.
I went through the saga on mine with an aFe intake and it ended up being some combination of bad MAF, a vacuum leak at the throttle body, and ultimately the MAF connector (3 issues that all were generated by removing the OEM intake and messing with 15-year old sensors/connectors etc). That was ~18 months ago and it has not thrown a single code since. Both the aFe and Toyota intakes have the same I.D. at the MAF sensor location, so the total volume of air (air velocity times cross-sectional area of the tube) should be the same. The Toyota tube does include some baffles that the aFe does not, with presumably could affect the overall flow and turbulence of the air near the MAF, but it has not been an issue on mine. In my case, re-installing the stock intake would have retained the CEL problem, as the MAF connector would have still been broken simply due to the act of removal.
When going through this personally I went through the effort of running a volumetric efficiency test (showing that my overall MAF readings were fine), and had several folks on the 100-series forum told me the aFe intake was the problem (it wasn't). Unfortunately, the age of these vehicles means that some things will be already broken or having other issues (hoses, wires, plastic clips, connectors) prior to the modification, or will break during the modification, leading to other problems which can be hard to diagnose.
- Thread starter
- #28
Happy new year everyone!
After replacing a lot of vacuum lines, doing a lot of spraying and looking at fuel trims with what appeared only to be tiny leaks around the throttle body, I found that the lights would go on less and less every time I would mess with the intake tube, take it on and off, etc. The jumps in the fuel trims were so tiny, but it was the only thing I had going at all. The trims would also go down slightly when spraying the supplied T fitting which joined a few lines together that otherwise are attached to the intake box itself.
In the end, I suspect the supplied AFE intake worm gear clamps may not be very good. Or maybe the intake tube itself is somehow warped? Maybe I was lucky when I first installed this intake, as it gave me no trouble for almost a year. For how tight the the clamps seem to need to be, they don't feel very good when tightened that hard. Anyways, the lights would return almost always after a lot of idling and slow city driving. For the hell of it, I swapped on the factory intake system, and knock on wood, it's been a week with no lights and no changes in driving habits. I'll continue to monitor this as I'm headed to the UP at the end of February.
After replacing a lot of vacuum lines, doing a lot of spraying and looking at fuel trims with what appeared only to be tiny leaks around the throttle body, I found that the lights would go on less and less every time I would mess with the intake tube, take it on and off, etc. The jumps in the fuel trims were so tiny, but it was the only thing I had going at all. The trims would also go down slightly when spraying the supplied T fitting which joined a few lines together that otherwise are attached to the intake box itself.
In the end, I suspect the supplied AFE intake worm gear clamps may not be very good. Or maybe the intake tube itself is somehow warped? Maybe I was lucky when I first installed this intake, as it gave me no trouble for almost a year. For how tight the the clamps seem to need to be, they don't feel very good when tightened that hard. Anyways, the lights would return almost always after a lot of idling and slow city driving. For the hell of it, I swapped on the factory intake system, and knock on wood, it's been a week with no lights and no changes in driving habits. I'll continue to monitor this as I'm headed to the UP at the end of February.
- Thread starter
- #30
I used a socket as well, to the point of where the worm gear was skipping on the clamp portion, which to me seemed like max tightness. Maybe my silicone couplers are also messed up?
I may reach out to AFE to see if they would have any suggestions but for now I'm just kinda stoked that it isn't the fuel pump. The factory intake is noticeably quieter all around which is both nice and sad. lol There is less throttle response as well.
I may reach out to AFE to see if they would have any suggestions but for now I'm just kinda stoked that it isn't the fuel pump. The factory intake is noticeably quieter all around which is both nice and sad. lol There is less throttle response as well.
They should give you a warranty claim on it. Worth it for a $350 intake.
I had p0171 and p0174 that were really bad, my ltftl and stftl were off, additionally I had p0420 p0430. I had random misfires and p0441 at one point too. I fixed the 171 and 174 by replacing intake manifold gasket and rubber sealers on injectors (on bank 1 only for now). I also had a leak on bank 1 valve cover (replaced). I changed the o2 upstream and downstream sensors. One upstream sensor was stuck lean so I had to replace again for a working one. The p0441 ended up being bad connector to the purge valve (located on bank 1 side of engine). After doing all that I still had p0420 and p0430 stored. I bought 4 o2 spacers and stacked 2 together and put it in post cat o2 sensor locations on both banks. After doing all that my gas mileage went from 10.5 to 15.0 in city and no more codes. I suspect I still have tiny leaks somewhere in exhaust causing the p420/430 otherwise. But since there is no loss in power after fixing with spacers and good acceleration (pending I have 33s and no re-gear) I won't do anything about replacing manifolds/cats.
