bluestreak701

I have a 2000 4runner 4x4 Limited California emission spec...
Well, I have had the P0171 CEL code (bank 1 too lean) off and on now for over 3 months. Since the first time it popped up I have started with cleaning the MAF sensor and also cleaned the thottle body. The code still returns after getting cleared and lately the truck is noticeably sluggish on acceleration only to feel it "kick in" about 5 seconds later. I suspect it is the front O2 sensor that is causing the problem. What do you guys think?

If that is the problem, what is the best solution? I could replace the stock narrowband sensor for about $190 off of urdusa.com . Of course the front sensor on the CA spec 4runners is the most expensive. The other option is to possibly upgrade to a wideband O2 sensor that can function as a replacement to the stock sensor since I plan on installing a supercharger and URD fuel mods anyway in the near future. I was looking at some of the PLX devices but am really not sure how many of the features are truly useful.

Comments??

Thanks,
Kevin

MTL_4runner

Sometimes a cleaning does not work and the MAF does need to be replaced. If you are convinced it is not the MAF then the only other item usually associated with that code is the O2 (A/F) sensor. You might consider trying a junkyard MAF and see if that helps at all too.

IS3004Runner

go get a used MAF from a junk yard. used camry/ES300 have the same maf as the 4runner. I got mine for like $50. CEL never returned again.

here's a quick link from car-part.com

http://www.car-part.com/cgi-bin/sear...erPage=1&iKey=

bluestreak701

Thanks for the tips guys. I didn't know those cars used the same MAF sensors, which should make it a lot easier to find.
Going to pick one up this week and see if that fixes the problem! Will let you know!

Kevin

bluestreak701

Stopped by the import junkyard today and ordered a new MAF sensor for 60 bucks. It should be here by Friday so I hope that solves my problem. CEL is on most of the time but occasioinally out. The truck is definitely still sluggish and I have a bad feeling that if it isn't this then it is the expensive front O2 sensor. We'll see, seems like lots of guys have issues with this P0171 code.

Unhappy99

Just to be sure, when you cleaned the MAF, did you clean just the obvious bulb thingy or did you actually clean both hotwires?

8422r4Runner

Seems like you might find the front 02 sensor at the same yard. Depending on the price it may be worth trying one.

??

dragr1

iTrader: (3)

Remember to disconnect the negative battery cable when installing the MAF, so that the ecu resets. Also, there is a new part number from Toyota for the MAF, b/c they've been having so much trouble with them, they redesigned it.

2000t4r

Do you happen to have the new part number, i get a discount at Toyota and I need to get a new MAF since I have been running around with my CEL on for the longest time now.

dragr1

iTrader: (3)

22204-07010

2000t4r

Thank you very much

bluestreak701

I installed the replacement MAF sensor today. Looks like the donor car was a camry but the sensor has the exact same part number as the one I took off of the 4runner. I unhooked the negative terminal on the battery while installing.

After everything was put back together I fired her up and the CEL is out! Looks like a success for now, hopefully it doesn't come back! By the way, the part number I used is 22204-21010. There was nothing visibly wrong with my old sensor so I guess something inside it is broken.

I would be curious to see what they changed on the redesign with the new part number.

Thanks for all the good advice!

Kevin

vince1540

Hi BlueStreak701, I have same problem as you were having on my toyota sienna 1999. I had replaced the MAF but still same code (P0171) and there is a hesitation (5 sec) like you were having when accelerating? Do you have any suggestion? Did you solve your problem? My car is also california emission.


Thanks,

dallison

o2 sensor

dallison

well, mine was a different code.

https://www.yotatech.com/forums/f2/c...ot-maf-208655/

BigRob215275

I have suffered with undiagnosed codes. I replaced the MAF the spark plugs and both catalytic converters at 60,000 miles. It quieted the code for a couple of months but they are back. 5 Toyota dealerships later I find a TUNEX technician finds the prob in 15 min. Fuel Pump in Tank on amp test is flat at 4 volts instead of 4 up to 10 back to 4. The amp ramp tests pump volume not pressure which can still appear normal.

BigRob215275

After nearly 6,000 miles dealing with my truck dying on the highway or in city sometimes completely at 60,000 miles and 5 Toyota Dealers and other suggestions Charlie in Cedar City Utah a NAPA TUNEX technician solved the problem in 15 minutes. He ran an amp ramp test to test fuel pump volume NOT PRESSURE. He changed the fuel pump and SOLVED an 18 month ordeal. TOYOTA and TOYOTA Dealers should be ashamed. I took the fuel pump apart and it was plugged by coffee grounds. Thanks to the Evil ones.

zipposrule

ive got a 95 taco with p0170 and ive tried cleaning and swapping the maf from another truck that didnt have the code. beside the code its getting really crappy fuel economy, 12mpg, any ideas?

kyryoz2

Hey everyone! Always make sure you aren't running an impregnated air filter. These can sometimes trip the MAF sensor and end up costing you $$$ trying to figure out what the heck is going on. To test, clean the MAF well (including the sensor bulb and connections) then reinstall and put on a decent dry filter. $40.00 for my fix and went with an AMSOIL EA nano fiber. AU3050