System 1 bank too lean? MAF sensor bad or what else can cause this?

Asked by Jan 10, 2012 at 08:01 PM

Question type: Maintenance & Repair

My wifes car will not run.  I had it scanned at Autozone.  If you unplug the MAF the car runs fine.  I put a reman MAF in place of the OEM and the car still wont run. To date I've replaced the battery, plugs, air filter, PCV valve and changed the oil(it was due).  I have also cleaned the IAC valve and the injectors.  Took off the resinator and stuck a bar through the CAT converter(it wasnt plugged).  Since the reman MAF didnt help I took it back and got a can of MAF cleaner to clean the OEM one...that didnt help either.  Anyone have any insite for me?  All this started with a drained battery due to park lights left on overnight....

2 Answers

55

The Mass air flow sensor wouldn't throw a code like that. It's coming from one of the O2 sensors. It can only be one of two things. Either you have a vacuum leak leaning the fuel mixture with air the car doesn't see entering the engine. Or you have a problem not getting enough fuel to bank 1. Could be a clogged injector or fuel rail. It's gonna take some diagnostics not something most people can figure out at home.

A bad MAF sensor can cause a lean bank 1 code. I've seen it today actually. Placed a rebuilt MAF sensor in a 3.8L Camaro and bam! Lean bank 1 code came on, idle was rough, car almost died. Took it out, placed a MAF sensor I had which I knew worked & code cleared, idle was perfect, no hesitation.

Your Answer

Add photo

Related Questions

  • my 2006 sienna running lean both banks 1 answer

    got code po171 and po174 running lean on both banks what can cause this problem

    2006 Toyota Sienna XLE Limited

    -

    Maintenance & Repair

  • Codes P0171 & P0174 (Too lean bank 1 & Too lean bank 2) 11 answers

    I have checked all vacuum lines, sprayed carb cleaner around MAP sensor, Intake manifold gaskets, between throttle body and manifold and around all vacuum points. All are tight. I've cleaned the MAF s...

    2002 Jaguar X-TYPE 2.5

    -

    Maintenance & Repair

  • Running lean 2 answers

    Okay so I drive a 2000 chevy blazer. I just replaced my o2 sensors because I went to auto zone because my check engine light was on & it said replace o2 sensor in bank one and two so we did. Now t...

    2000 Chevrolet Blazer 4 Door LT 4WD

    -

    Maintenance & Repair

  • All of Bank 1 misfiring 10 answers

    I have an exhaust leak I have replace 3 coil pack on the passenger side, cyl. 1-4 are not firing. I know because while truck is running I unplugged all the coil packs and the idle never changes. I kno...

    2008 Ford Explorer Sport Trac Limited 4.6L 4WD

    -

    Maintenance & Repair

Shortcuts

Search Maintenance & Repair Questions

Maintenance & Repair Experts

#1 Tom Demyan
Tom Demyan
Reputation 150,370
#2 FordNut
FordNut
Reputation 103,250
#3 dandyoun
dandyoun
Reputation 84,280
View All