P0171 code on 99 4Runner 3.4L

[Mountain Biker]

I used my OBD2 code reader and came up with this code which translated as running lean (P0171). I reset the check engine light and it appeared again. I changed the fuel filter, cleaned the MAF, changed air filter and the light still comes on after I reset it. I had a mechanic test it and he said the fuel injector on cylinder #1 was running sporatic. He used a professional grade injector cleaner on it and it went away but after it ran out, behold, the light (check engine) came back on again.

Has anyone out there ever replaced an injector on a 3.4L V-6. It is my wife's 4Runner and I need to get it fixed so I can sleep at night. I checked my Hanes manual and it really doesn't show a good breakdown of this important area. Does anyone also know how much $$ I am talking about?

Any help would be appreciated.

Thanks all, great site!

Moutain Biker from Texas!

[Mrbikerman]

Sorry, I have no advice on this one, but I had to say hello to a fellow mtn biker. Hope you get this solved

[Mountain Biker]

Originally Posted by Mrbikerman

Sorry, I have no advice on this one, but I had to say hello to a fellow mtn biker. Hope you get this solved

Thanks. I hope to get this fixed so I can go riding without the wife threatening to lock my bike up.

Later and happy trails.

[4Wheel]

O2 sensor?

[Mountain Biker]

Thought that might be it too but it tested good with an Ohm Meter. All were in specs. The mechanic that worked on it said that the #1 Cylinder fuel injector wasn't getting the proper amount of electricity. I was wondering if anyone out there has ever replaced any of these on the 3.4L.

Thanks.

[rgh2004]

this same code came up for me when my check engine light had come on. I was told it was running lean and that the problem was the air flow meter. Once that was replaced, the check engine light problem was taken care of. However, you might want to make sure that replacing this item does not affect idle speed, which is a new issue I am dealing with now.

rgh2004

[Mountain Biker]

How does it affect your idle? Sometimes in traffic the engine will just die. It will crank back up but I can't figure why the engine dies. Was yours doing that too?
Thanks for the help.

[askwhy]

Mtn biker, you hopefully have your 4runner fixed by now, but this happened to mine too.

I will admit that I know almost zero about cars, but I love my 4Runner (99 SR5 v-6 4WD auto) and will do whatever I can to figure it out!!! I bought a 4Runner from a less than reputable dealer...long story...anyway, when I bought it, the guy told me that the check engine light had come on due to a bad O2 sensor but it had been fixed. As soon as I drove it off the lot, the light came back on...I took it back at least two more times. I was getting the same lean code and my engine was stalling periodically just like you say yours is, esp when I would get to a stoplight or slow down to take a sharp curve. Turned out to be the Air Flow Meter like RGH said. Dealer fixed it and have had no more problems with that. So give that a shot if yours is still giving you trouble. Good luck

[Mountain Biker]

Thanks for the post/info askwhy. The light hasn't come back on since we came home from a 1300 mile trip but I'm definately going to look into that Air Flow meter. I'm like you too concerning this 4Runner. It is my wife's 4x4 but I take care of it.

Thanks again askwhy and I'll let you know how it turns out.

Mountain Biker

Originally Posted by askwhy

Mtn biker, you hopefully have your 4runner fixed by now, but this happened to mine too.

I will admit that I know almost zero about cars, but I love my 4Runner (99 SR5 v-6 4WD auto) and will do whatever I can to figure it out!!! I bought a 4Runner from a less than reputable dealer...long story...anyway, when I bought it, the guy told me that the check engine light had come on due to a bad O2 sensor but it had been fixed. As soon as I drove it off the lot, the light came back on...I took it back at least two more times. I was getting the same lean code and my engine was stalling periodically just like you say yours is, esp when I would get to a stoplight or slow down to take a sharp curve. Turned out to be the Air Flow Meter like RGH said. Dealer fixed it and have had no more problems with that. So give that a shot if yours is still giving you trouble. Good luck

[Brian R.]

My 2000 4Runner P0171 code was cleared by cleaning the MAF meter