Check Engine Light: Auto Zone says running lean
 

I was out riding around and my "Check Engine Light" pops on out of the blue. I have a 2000 Blazer with a 4.3. I noticed a hesitation lately when I need to get on the gas a little bit, but now its worse. I ran over to auto zone as soon as I could and had them run their computer on it.
A P0171 code came up and the man printed the OEM Number reference paper telling whats wrong.
This paper list's 11 different brand names of cars wich are all import except for one that list's "Domestic". He goes directly to the Infiniti section and tells me its one of these:

Fuel Injection system too lean- bank 1
(Cylinder Number 1 denotes bank 1)

Probable cause
aa1.- Low Fuel Pressure or restricted flow
aa2.- Ignition system fault
aa3.- Large vacuum leak
aa4.- Faulty MAF sensor

This is Exactly what the paper says word for word on the "Infinity" section, that the man marked on the PO171 Number Guide.
Any suggestions or help would be great, Thank you all very much for reading. By the way, Great web site!! I wish I knew about this place along time ago.
Chuck

Have a read through this:
P0171 - Fuel Trim System Lean Bank 1

Thanks swartlkk for the post reply, that page is a big help.

Chuck

Let us know if you have any questions through the diagnosis.

I will, I just hope its nothing I did when I ran it through an automated car wash. I did it so I could get all that salt and slag out from underneath it. Its never bothered it before though.

Thanks again, Chuck

i had the same problem with my 2000 blazer. i had it checked out and everything. i replaced the o2 sensors and it popped back up. i solved the problem by replacing the maf sensor. they are super sensitive to anything getting on the sensors inside them. also if you are running an air filter that is oil charged i would suggest switching to a dry charge filter.

171
 

The same thing happened to me, I thought it was my 02 sensors. But it ended being a vacuum lime completely unplugged. Just gotta look around under the hood.

Wouldn't the maf sensor cause it to be lean on both sides of the engine?
I have the whole K&N intake kit on it, never had a problem with it before though. I was going down the 152 today, she spit and sputtered a bit, the check engine light went off and now it runs like it used to. I have know idea what its problem is, maybe water in the gas or it just has a mind of its own.

Does your blazer have the hard hoses or the soft ones?