I know what this code (P0171) is and a few of the things to look at. 2000 Tacoma 3.4 L 5 speed 4x4

The thing is it only happens on days I use the Truck for a longer then normal trip. Say of over a 100 miles in the summer. I had about 800 pounds in the bed. The truck seems to run fine.

If I let it sit over night the code most times clears it self on start up I cleared it this time after I read it.

No other codes at this time.

Just curious if any one else had this??

Thanks

The truck

 

Here is a list of things to check out.
It could as simple as a pcv valve.
This from a 4runner but is exactly the same.

http://www.ncttora.com/fsm/1996/SIL/...e/cip0171p.pdf

 

Thank you much I have all that information but I think I know what it is now.

Just like me the ECM is as confused as me.

Now I will need to see if my theory proves correct or not.

 

seen these alot. i would start with cleaning your MAF. i bet its dirty. also if your running a K&N air filter. get rid of it. oily filters will dirty your MAF

 

Thanks

Truck is pure stock use wix filters.

If you think it is the MAF sensor I guess it is time for a new one unless I should be cleaning it once a month.

With a new one will I still have the same problem??

 

trying cleaning it 1st with a MAF safe cleaner they sell at auto stores. you can remove yours and see if it is dirty with a flash light. it will look like alot of lint around the sensor. the sensor you wanna look at is down inside the tube of the MAF. theres one on the outside you can see really easily and one inside the tube

 

Thank you .

I just had cleaned it and know what to look for the first weekend in May.

I must have a problem that it gets dirty so fast.

I guess it won`t hurt to have a spare one so I can rotate them every 2 weeks or so. Installing a cleaned one every 2 weeks should I hope cure the problem.

Using the truck yesterday running local errands maybe 40 miles in8 hours no issues.

 

Did you make sure to clean the two small elements down inside the MAF, and not just the larger thermometer type element? The first few times I cleaned the MAF I only cleaned the larger element which of course did not help the situation. Not until a little more poking around did I realize there are other pieces that get dirty. Good luck....

 

i have the same code on my truck and i have cleaned the maf and throttle body and put new plugs and wires. Its got 95k on it and im leaning more towards a dirty injector in cylinder one. It feels like its worse the more throttle i give it. Am i on the right track? other than that truck runs great.

 

you really dont have a problem, they just get dirty over time. i wouldnt buy a second one cuz they are kinda expensive. if cleaning this one works. just keep driving and dont worry bout it.

more info would help on your truck. year/engine/mods/etc

 

1999 Tacoma 4x4 3.4L 5 speed, no mods to engine everything under the hood is stock.

 

after cleaning the maf, did you clear the code and did it come back?
just in case. heres a link on how to clean, go down a little bit
http://www.4x4wire.com/toyota/mainte...ntenancep5.htm

what code(s) do u have

 

I have the P0171 code, and no i didnt clear it but i can still feel it skipping. I am certain i cleaned it properly. The reason i asked about the injectors being clogged is thats the only code i am getting. If it were the sensor wouldnt i have a skip in more than just cylinder 1? I am just asking i have done a lot of searching on here for this code but it seems as though mine is the only one who has just one code and skips when it feels like it, sometimes at idle and sometimes when i catch a lower gear to go up a hill. If u need any more info from me that im leaving out just ask, i dont have internet at home so i will answer asap. Thanks for your time

 

how do you know its missing in only 1 cylinder? i would clear the code and see if it comes right back (CEL) pull the code to make sure which code your getting and we can go from there

 

will do , i will let you know asap....i just assume its one cylinder since thats the code im getting but i will reset it today and hopefully will have an answer by tomorrow night. thanks

 

p0171 doesnt mean its just one cylinder. p0171 one means you have a Lean Condition in Bank 1 not cylinder 1. when its showing lean condition, u have to go back on the list of components and see which will affect the entire side (bank 1) MAF, Intake Tube, and so on

 

ohh okay, i miss understood the code..ha i feel stupid, alright so i have put lucas fuel injector treatment in last 2 tanks and the skipping has stopped but still have code after resetting it. I dont think ill worry about it to much now since i got 19.7 mpgs last tank. Thanks for the help

 

No matter what I do this same code comes back.

The truck is fine while I drive it local put on about 300 miles driving no more than 15 to 20 miles jaunts . No codes runs good

Does the computer get adjusted to that type of driving??

All most without fail if I take it on a longer trip say a nice 200 mile about 2 hours one way with some interstate 65/70 mph.

Before I get home the cel will come on. Now if I am to tired to pull the code when I get home . Go back to the normal style of driving the light goes out by itself.

In any case I am curious to see what the code is.

Just changed the MAF sensor thinking I just can`t clean it correct went through and put all new exhaust gaskets from the crossover pipe back.

Since I had the front Air fuel sensor and the rear O2 sensors out to replace the gaskets I put 2 new sensors in.

This is not a major problem because if I don`t take the truck on a longer then normal trip it is fine.

So I just make sure all the sensor test run before going for emission testing get my sticker and I am good for a year.

Just I would sure like to know what causes the issue.

Thanks for the input

 

this is all that could cause p0171
- air induction system
- injector blockage
- Mass Air Flow meter
- engine coolant temp sensor
- Heated oxygen sensor (bank 1, 2 sensor 1)

if you already cleaned MAF and or replaced it. we can rule out MAF
looks like you replaced the A/F and O2 sensors so we can rule that out
next i would look into any air leaks like a vacuum hose to your intake tube between the MAF and Throttle body. check around the Plenum as well

 

i pretty much give up The only thing left to replace is the ecu .

Air intake system is now all new along with 6 rebuilt injectors all the vacuum hoses and clamps new wires plugs. coolant sensors also were changed

Since this truck will not pass emissions and the complete lack of yard parts due to the buy back . I sort of draw the line at how much I all ready spent.

Such is life I guess.

My theory is that perhaps the ecu is getting hot on long trips from the exhaust causing the ecu to see problems that don`t exist