pfdaxe

I get a 0171 code when I'm in vacuum and around 2000 rpm. This is something new as I used to get this code when running too lean before adding the URD fuel mods. Also, it only appears to happen when first driving the truck after sitting for a bit. If I'm in and out of stores or driving around all day it doesn't trip the code. Could this be a closed/open loop issues or possibly a vac leak? The truck runs good.

Elvota

Do you have a FSM giving you the steps to troubleshoot this code?

If not, PM me an E-Mail address I can send an attachment to and I'll shoot over the related pages.

Also, ScanTool.net is located in Phoenix, AZ and they have several laptop interface cords for the OBDII port. Cost is reasonable, and maybe that would give you more "real time" information in regards to your intermittent code issue.

MTL_4runner

My suspicion is a vacuum leak given that you have a supercharger. Check all the gaskets and hoses thoroughly and use a can of carb cleaner to listen for changes in engine RPM that might indicate a leak.

4rx

since you have S/C, i remember i read somewhere on here that has the same code and turned out o-rings... hope it helps..

MTL_4runner

Good call.....if it is a 1st gen supercharger (ie the light gray type) then they often have an o-ring gasket that can fail thus causing a vacuum leak and later your P0171 code. If you have that version of S/C then it's definately worth checking out.

pfdaxe

Nope. I have the 2nd gen s/c (black one). What o-ring anyway??

MTL_4runner

The 1st gen S/C was a 2-piece design which was sealed with an o-ring while the 2nd gen S/C was a single piece hence no o-ring.

I still say you have a vacuum leak somewhere (throttle body gasket, intake gasket, vacuum hose, etc).

pfdaxe

After a couple of months of checking and eliminating different items that could be causing my 0171 code....

I found a couple small exhaust leaks on my TRD stainless muffler at the seams. I find this odd since the trucks never exposed to harsh winter weather and being a supposively good quality TRD product I'm suprised. I'm also somewhat suprised that this caused the code. I fixed the small leaks.......and no more code. Anyone heard of a small exhaust leak throwing a 0171 code??

Stevo3

No, I have never heard of that. Since the first o2 sensor is what throws that code. Its telling it its too lean. Since your muffler is even past the 2nd o2 sensor, it should not have affected that at all. When was the last time you cleaned your MAF? If you need a hand with anything Im also located in AZ, the Surprise area. I would still look for a vacume leak or something other. Possible even a bad gasket possible between the s/c and intake manifold. Or even between the TB and s/c. If you need a hand just hollar.

pfdaxe

Stevo:

Thanks. I thought it sounded odd, but the code hasn't come back since I sealed the leak. I clean the TB and MAF every few months and just did it a couple of weeks ago and also replaced the TB gasket. But the code was still there at that time.

Are you any good at tuning with the R4 software from URD?? I still haven't found a good tuner and I know I could get more out of it if it was dialed in just right.

I'm not too far from you as I live in the Arrowhead area north of 101...

pfdaxe

I quess I spoke too soon....the CEL stayed off for a couple of days. Now it's back doing the same thing