dpassino

I threw a p0171 code the other day (too lean bank 1) and did some research and read that maybe MAF was dirty, so I cleaned it and changed my air filter... got and oil change and new fuel filter...

The light went off almost instantly after cleaning my MAF and stayed off for about 260 miles and just came back on. same code P0171.

What else might it be? O2 sensor? I just replaced them all about a year ago.

Any way I can be certain if maybe MAF is bad or O2 sensor without having to replace both?

Leo_Koneval

iTrader: (4)

I just went through the same thing, and it was the MAF. Its strrraaaange though, because if the MAF was bad then both banks would be lean or rich, but mine was just lean in ONE bank and I assumed it was O2 sensors or something other than the MAF.

But after waiting a while and driving the car a few more weeks, my car started to stall and die at lights. And the idle would be extremely rough, like it would jump up and down until it just died. And then soon my car wouldn't even start for some reason. And so I got it towed to the shop thinking I blew my engine or something and it ended up just being the MAF.

dpassino

So cleaning it prolly gave it a little boost to turn off my SES light but eventually came back on..

I occassionally will experience a problem when I try to start car, nothing happens for about a second, then it starts up, idle has a small shake but not rough and when sitting at a light while in "D" the car will have a slight vibration once in a while... sound familiar?

Quick question for you then, I have a 99, I notice you have a 97, did you have to reflash the ECU at the dealership after new MAF?

tonyinfiniti

just for giggles, try adding a ground wire to the MAF's existing one... I was surprised at the difference

Leo_Koneval

iTrader: (4)

I didn't have to reflash the ECU, but I also used a aftermarket MAF but I'm not sure if that makes a difference. You see, what happened to my OLD MAF was that it got to a point where it shorted out and was beyond cleaning or adding wires.

But up to the point where before it died which caused my car to die, I noticed that while accelerating the RPM would shake. Like it be at a steady 2000 RPM and then all of a sudden it would shake up and down between 1500 and 2000 RPM for like 3 seconds until I let go of the gas or step on it harder.

dpassino

That hasn't happened to me yet. I do notice though when I give the car some juice and revs up to 3k, hesitates a little and then revs up some more. I'm just trying to avoid replacing the maf and an o2 sensor.

question though, maybe you know.. Bank 1 o2 sensor, is it the one that's reachable from the engine compartment, or is it the one that's near the y-pipe bend before the flex section?

UPDATE: well I just ordered a replacement MAF, when it comes in, I'll install and see what happens. Hopefully will fix my problem.

tonyinfiniti

it is the one in front, easy to get to.

cashoit

I dont trust them Ebay MAFs. Too many mixed reviews. Good luck with it man and let us kno how it works out. I doubt its the o2 sensor

dpassino

ya know, I was driving down the road and the Light popped off by itself.... Again! LOL

I don't know wth is going on. when I cleaned it, it instantly went off, then at 260mi came back on, and at 280mi went off and been off for about 15 miles. I'll accept delivery of the MAF I ordered and will hold off on installing and drive around for a few hundred miles and see if it comes back on. My car is possessed!

dpassino

I installed the received MAF and my car's idle was TERRIBLE, and it smelled of rotten eggs and sulfur terribly! I am going to return the MAF since it's not working.

I put the old maf back in and the idle is back to normal, but upon inspecting my original maf, i did notice a walnut sized hole in the black plastic housing. Could that be considered a "leak" which may be throwing my p0171 code?

dpassino

maybe some more advice from .org members?

The guy told me i could return the maf, but he said that when I put in the new maf and if I had a rough idle and rotten egg smell, this is probably a result of the computer fixing the fuel/air ratio causing rough idle and the cat is burning through stale carbon deposits which would be causing the smell.

Is this possible true?
I mean the idle is so bad that the car feels like it's going to stall out with the new MAF and the exhaust stinks terribly!! I'm not sure if I should drive around with it like that. I might blow something up? LOL

UPDATE: Well I drove around about 50 miles with the new MAF. I don't have the rotten egg/sulfur smell anymore, so that's good, but the car when stopping at a light wants to stall, and did stall twice. However I didn't have fuel cut off or lack of power when driving. It drove perfectly fine even at WOT

I have another problem now. I think my alternator is going. I turned on my a/c, my bright lights and tapped my brake while at a stop and the car stalled. for the love of god! I turned on the car, disconnected the battery cable, and turned on the lights and the car died. This also may be the cause for my rough idle perhaps. Like i said, the smell is gone from the exhaust, the car has no accel problems, just the idle. Perhaps the alternator is having problems keeping up with the dead stop with brake lights on. As a test, I came to a dead stop, turned on the high beams and the radio and dome lights and car damn near stalled out. There goes a portion of next weeks paycheck

xsmooth69x

when my alternator was going out my car did the same thing. actually my alternator burnt out because the cable on my wiring harness to my alternator melted.

i had a pretty big system in my car to btw.

but anyways i would get the alt rebuild get a new sensor reset the ecu and you should be fine.....?

dpassino

I think I'm going to have bite the bullet and bring it into a shop. I've replaced the sensor, it no longer smells, and no longer tries to stall out. Checked the alternator, and it's functioning at the correct dc voltage as well as the battery Was driving around today and the SES light came back on, same code p0171.

Could it be a cat issue? My cat is original 11 years old. Would a bad or gunked up cat cause p0171? I'm pulling at strings now. My o2 sensors aren't very old. about a year. I'm doubting it's them, but who knows. I don't hear any abnormal vacuum leak sounds in the engine compartment.

cashoit

I assume u have performed the TB cleaning.

Since u have been gettin the too lean mix, u have an air issue. I think the MAf u got was crap. A good used MAF would work instantly. Check yur MAF harness. U try some chevron in the fuel tank, make sure the injectors adn spark plugs clean.

Told u man, I dont trust them EBay MAFs, too many mixed reviews.

dpassino

Yes, I did a TB cleaning.

Well the new code that was in the code reader was p0134 which points to o2 sensor bank 1 sensor 1. I had them all replaced less than a year ago. I don't see how it went bad already. A mechanically inclined friend told me perhaps the car is relearning the new fuel/air mix and it threw the p0134 code since the o2 sensor needs to update the readings as well. The light went off this morning on it's own, and I've driven about 45 miles since so far. No code again yet. Hopefully won't happen. LOL

The car no longer smells or has a rough idle, actually it's quite smooth, along with acceleration, I don't feel a loss of power or anything on the contrary, she seems to be pulling a bit bitter especially up hills. Hopefully what he told me has some truth to it and my problem is solving itself... hopefully hehe.

dpassino

p0134 came back

Bank1 Sensor 1 02 sensor

I have CALI Spec, which sensor?
Is it the east to reach one right behind the radiator, or the hard to reach one before the flex section of the y-pipe?

cashoit

Yo man, jus pull each o2 sensor and wipe it off. We did that with my boy camry, his code went away next day never came back