P0171 help

[lucky'99]

My CEL has been on for a month and just got the code pulled and it's P0171 - system too lean bank 1

Back on 2/20/10 I had the air fuel sensor replaced @146164mi (I failed the smog check due to this code..). Got the sensor replaced and passed.

So now the same code is back and I am at a loss to what is causing the same code to come back. I am not noticing any power loss.

Here is what I've done resently:

Oil change and filter (9/11/10)
Spark Plugs (9/12/10). I put the correct type of plug.
Fuel Filter (10/2/10)
Air Filter (10/2/10)
PCV Valve (10/7/10)

Any ideas as to what it can be??

 

[BTO]

Try cleaning the MAF sensor and reset the code. Then drive it around a while to see if it comes back.

 

[lucky'99]

Try cleaning the MAF sensor and reset the code. Then drive it around a while to see if it comes back.

Thanks BTO. I'll pick up some MAF spray and give it a shot.

 

[TheDurk]

Clean your throttle body, too.

 

[lucky'99]

Clean your throttle body, too.

I cleaned it not that long ago, less than a month..probably should have put that on the list of stuff I've done.

 

[lucky'99]

bump


So besides cleaning the MAF and re-cleaning the throttle body, any other ideas?

I have the stock air box and filter, so I was going to try and put that back on to see if it's my air intake is the problem.

Could it be a vaccum leak, or exhaust leak? That A/F sensor is bad after only 8 months? Should I get some of that pour in the gas tank injector cleaner?

Anyone have any other ideas, because I am at a loss.

 

[BTO]

Are you bumping because cleaning the MAF and TB did not fix it? Yes a vacuum leak can cause this. I don't know if an exhaust leak can but I doubt it.

 

[lucky'99]

Are you bumping because cleaning the MAF and TB did not fix it? Yes a vacuum leak can cause this. I don't know if an exhaust leak can but I doubt it.

Yeah, I cleaned the MAF the next day after I posted this. It was pretty dirty. I pulled the TB and it wasn't that dirty (I cleaned it about a month ago), but I gave it a light cleaning. I made sure everything was plugged in and tighten properly.

Maybe my MAF is bad?

 

[AddictedOffroad]

How did you reset the code after you cleaned it? With a diagnostic scanner or what?

What aftermarket filter or you using, and are you oiling it like a K&N?

 

[lucky'99]

Before I started the work, I disconnected the battery. That should have cleared it out. It was disconnected for a good 30 minutes.

I believe it's an oily...

 

[BTO]

I thought you were using a paper air filter since you posted you replaced it. If it's like addict says and you are using a oily type then that might be the problem. Those have a bad habit of fouling MAFs.

 

[AddictedOffroad]

Before I started the work, I disconnected the battery. That should have cleared it out. It was disconnected for a good 30 minutes.

I believe it's an oily...

Oil style filters are notorious for allowing oil to get on the MAF, then dust gums it up making it read incorrectly.

Have the code cleared with a diagnostic scanner to make sure.

FWIW, I run a aftermarket filter as well. But, I do not oil it. Instead I run a pre-filter sock over it to keep more dirt out.

 

[lucky'99]

On my CAI has a oily cone. My stock box has a stock paper filter. I haven't put the stock box back on, but I'm going to do that this weekend.

 

[BTO]

Don't forget you also need to clean the MAF again.

 

[lucky'99]

Thanks guys. I'll re-clean the MAF and see if I can look for a vaccum leak. i'll let you know what I come up with.


Scotty - Where did you pick up that sock from?