OBD Code 0171

[2DaMtns]

So my check engine light came on months ago, and I haven't been able to figure out what the problem is. It started out as not a big deal, then started acting like it was not getting any power to the rear wheels. When I would shift from reverse to drive, or try to pull out in traffic, it would rev up and act like it was in neutral, and then all the sudden catch and jerk and then drive fine. Then, it started bucking and not running very good when it was warming up, and the RPM gauge jumps back and forth a couple hundred RPM at idle. Finally, it developed a "dead spot" in the throttle. What I mean by this is that there is one spot at about 3/4 pedal at which the fuel response completely goes out, like it isn't getting any gas at all.

So, I took it to a shop and got it scanned, and it threw a code saying the O2 sensor was out. So, I changed it and took it back to the shop and they cleared the code, said all was fine. Later that day, the light came back on and the shop was closed, so I took it to a parts store and they scanned it as an 0171 code, system too lean (Bank 1). I BS'ed with the guy there and he gave me a few ideas. Since then, I have replaced the ECT sensor and TPS, cleaned the MAF sensor and throttle body, and replaced the air filter.

Today, I unhooked the battery and touched the cables together to drain the system. After I hooked the battery back up, it would hardly run. The longer I drove it, the better it ran, but it still had the dead spot in the throttle. I am at a loss here and already came close to trading it in once cause I am getting so frustrated. Anyone got any ideas to help me? I was gonna change the fuel filter, but the Toyota garage told me I don't ever have to, and odd idea to me, but whatever. I am about to call it a loss and get something new if I can't fix this, so please help me out if you got any input.

 

[RunnerUp]

go ahead and change your fuel filter, i changed mine at 110k and it was NASTY. how good did you clean your MAF?

 

[Ron Helmuth]

yes change the fuel filter

Yes I agree-have the fuel filter changed but I would politely say you are throwing parts at it in hopes of solving the problem. We have all done it and we hear your frustration, and we are here to help you out. Please don't take a loss on your Runner-no need I feel certain- out here on the World wide Web.

I would recommend a dealership at bare minimum just to diagnose the trouble. Establish a relationship with the service writer and detail what has already happened and that you would expect them to stand behind their diagnosis.

For example if they say it needs new spark plugs and wires-have them commit that this is all it will cost you for diagnosis-then that once you buy the plug and wires (yes probably at their inflated prices), that is all you will have to spend on parts. If it continues to act up don't wait even a day, take it right back and hopefully you can demonstrate the trouble easily.

If it's not intermittent-then a competent shop should be able to diagnose and fix this. I don't do my own work-I have to find those competent shops. If you need help finding that shop-no matter where you are-this forum will help you out.

Good luck and keep us in the loop-we have all been frustrated and this is likely some small item causing this on your vehicle.

 

[2DaMtns]

I cleaned the MAF as well as I could. I bought some official MAF sensor cleaner and tried to take it out first, but the damn cheap screws holding it in stripped out. So, I took the whole tube assembly out and cleaned it as well as I could. It looked much cleaner and I couldn't see any visible gunk left on it, but I obviously couldn't see in there that well.

And yes, I am about to take it to the dealer. I have rationalized the spending thus far because I figured most of the parts would need replacing soon, so I haven't done any harm to anything other than my wallet. But I can't keep doing this forever. I will keep everyone posted on whatever I figure out.

 

[RunnerUp]

thats prob. your problem, get those screws out and actually clean the MAF itself, there are wires deep inside that you need to clean as well. and a 0171 code is for a dirty MAF... before you take it to a dealer, get those stripped screws removed and clean it yourself, unplug your battery and rehook everything up

 

[Ron Helmuth]

Okay best of luck with the dealership Damtns and where are you?

Like if you are here in Colorado for example I have lots of folks to refer you to-

I reread my post and apologize if that came off as a bit harsh-just trying to be helpful dude.

I did have a local dealership here replace my MAF sensor on my own vehicle about 6 months back-after it threw out a Check Engine Light- and they blamed it on letting the air filter get too dirty-and it barely had any dust on the surface of the stock filter.

I have since gone to a TrueFlow filter and it seems to "trap" the dirt better in the material of the filter.

 

[2DaMtns]

I will try getting the MAF off and cleaning it more thoroughly. And Ron, you didn't come across as being harsh. Hell, if I had gone somewhere competent to begin with, I would be done. But I had had two different shops with the good high dollar scanners scan it and say it was the O2 sensor, and that itself was more expensive that everything else I have done to it. Unfortunately I am in WV, so shops in CO aren't going to help much. Thanks again for all the input guys.

 

[Grreatdog]

I started getting that code in my '99 everytime we drove it on the highway. Cleaning the MAF cleared up the code and made it run a lot better. It is definitely the first thing to try before throwing parts and money at the truck.

 

[2DaMtns]

UPDATE

Well, I went ahead and replaced the fuel filter since the old one was original from the factory, with 120k on it. I poured the gas out of the input side of it, and it looked like coffee grounds almost, it was nasty. Still didn't help too much with the problem, as it still is doing the same thing. Something odd, to me at least, is that it is much worse when I unhook the battery to clear the code and then hook it back up. But then, if I run it for a little while, it gets back to running ok except at the one spot on the throttle. Next in line is to get the MAF out and clean it better. If that doesn't fix it, it's off to the dealer to be left until it is fixed. I will keep everyone updated.

 

[Ron Helmuth]

okay thanks for the update. Sounds like you are getting there.

Since you can see the gas has likely been dirty for awhile I would probably suggest also adding some Techron fuel injector cleaner- it is added to the fuel at fillup, a couple of bottles could not hurt to clean up your system. It is a quality product, I believe sold at Chevron stations or probably at auto parts stores also.

good luck