Hello all.
Vehicle is a 2006 GX470 Sport with about 117k miles.
Figured I'd post here with my journey with those two lean codes. I have done a lot of reading and know that it may come down to a variety of causes ranging from small vacuum leaks, MAF sensor, my aFe intake, fuel pump being weak, and more. I'm really just looking for other advice and things to check.
Initially the truck threw P0174 and I started looking for vacuum leaks on passenger side with none being apparent. Then a few days later after resetting the codes, it threw both side lean codes.
I have had the aFe intake on for approximately a year and have never experienced issues with it. I am suspicious that it is the cause but I will switch it for OEM intake if need be once I feel desperate enough.
I cleaned the MAF sensor and throttle body last year, and they were both visibly dirty at that time but never caused issues. I cleaned it again recently, but it was visibly clean. The MAF reads 1.5 gm/sec at key on, engine off. I used my techstream and compared it to readings others posted and it doesn't seem off. Regardless, I have a new Hitachi MAF on the way, hoping it'll arrive tomorrow. Will swap and go from there. I also used the techstream to check fuel trims. They are very positive both long and short at idle. However, at higher RPMs they go negative and steady. Both banks are very similar in their readings. I can post recordings from the techstream here if needed. I'll try to post some photos of the readings.
The other day, I started fiddling with all of the vacuum lines and intake tubes. I removed and cut the last few MMs of two lines that had tiny cracks on the end. I also removed and cleaned the intake tubing. I sprayed brake parts cleaner ALL over the engine and intake manifold, all lines, etc with no changes in idling. The truck is lightly seeping oil from under the intake manifold, but it's been visually the same for over 2-3 years. There is a little red tab sticking out that I will try to take a photo of, this is under the intake manifold and appears to be the gasket. But when spraying there, nothing changes.
The truck runs great and smooth. Besides the lights it feels no different than normal. Fuel economy appears to be normal. The oil doesn't smell any more of gas than my other 3 vehicles. The other day I took it out on a highway drive at 75 for about 15-20 mins. The lights went away. They returned in stop and go city driving and longer idle times. They disappear again if driven at higher speeds and steady RPMs. At this point, I think I either have some tiny vacuum leak that I haven't been able to pinpoint... or the aFe intake has all of a sudden decided to annoy the computer? I guess I could also check fuel pressure, but I understand that's not the easiest on these motors due to not having a dedicated valve. I am really hoping it is not the fuel pump at my relatively low mileage. Appreciate anyone's help.
Vehicle is a 2006 GX470 Sport with about 117k miles.
Figured I'd post here with my journey with those two lean codes. I have done a lot of reading and know that it may come down to a variety of causes ranging from small vacuum leaks, MAF sensor, my aFe intake, fuel pump being weak, and more. I'm really just looking for other advice and things to check.
Initially the truck threw P0174 and I started looking for vacuum leaks on passenger side with none being apparent. Then a few days later after resetting the codes, it threw both side lean codes.
I have had the aFe intake on for approximately a year and have never experienced issues with it. I am suspicious that it is the cause but I will switch it for OEM intake if need be once I feel desperate enough.
I cleaned the MAF sensor and throttle body last year, and they were both visibly dirty at that time but never caused issues. I cleaned it again recently, but it was visibly clean. The MAF reads 1.5 gm/sec at key on, engine off. I used my techstream and compared it to readings others posted and it doesn't seem off. Regardless, I have a new Hitachi MAF on the way, hoping it'll arrive tomorrow. Will swap and go from there. I also used the techstream to check fuel trims. They are very positive both long and short at idle. However, at higher RPMs they go negative and steady. Both banks are very similar in their readings. I can post recordings from the techstream here if needed. I'll try to post some photos of the readings.
The other day, I started fiddling with all of the vacuum lines and intake tubes. I removed and cut the last few MMs of two lines that had tiny cracks on the end. I also removed and cleaned the intake tubing. I sprayed brake parts cleaner ALL over the engine and intake manifold, all lines, etc with no changes in idling. The truck is lightly seeping oil from under the intake manifold, but it's been visually the same for over 2-3 years. There is a little red tab sticking out that I will try to take a photo of, this is under the intake manifold and appears to be the gasket. But when spraying there, nothing changes.
The truck runs great and smooth. Besides the lights it feels no different than normal. Fuel economy appears to be normal. The oil doesn't smell any more of gas than my other 3 vehicles. The other day I took it out on a highway drive at 75 for about 15-20 mins. The lights went away. They returned in stop and go city driving and longer idle times. They disappear again if driven at higher speeds and steady RPMs. At this point, I think I either have some tiny vacuum leak that I haven't been able to pinpoint... or the aFe intake has all of a sudden decided to annoy the computer? I guess I could also check fuel pressure, but I understand that's not the easiest on these motors due to not having a dedicated valve. I am really hoping it is not the fuel pump at my relatively low mileage. Appreciate anyone's help.
