How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Eric Your Own Question
Eric
Eric, Automotive Repair Shop Manager
Category: Chevy
Satisfied Customers: 29985
Experience:  20+ yrs. experience as repair shop manager and technician.
3195632
Type Your Chevy Question Here...
Eric is online now
A new question is answered every 9 seconds

2000 Chevy Blazer: vortec..intermittent..maf sensor..po171..too lean).

This answer was rated:

Hello, I have a 2000 Chevy Blazer with 4.3L Vortec Eng. Here's the problem(s): The Check Eng light is intermittent with a codes PO101 (MAF sensor) & PO171 (Sys. too lean). Also the fuel pump is making a very high pitched sound and the truck hesitates on acceleration with the engine cold. Could all these problem be related to the fuel pump? --- Thanx in Advance,Customer

Hi,

 

While the lean code can be caused by a faulty MAF sensor and/or weak fuel pump, a MAF sensor code wont be caused by a weak or faulty fuel pump.

 

Lean codes are generally caused by a vacuum leak, weak fuel pressure, intake air leak, faulty or dirty MAF sensor, or intake manifold leak.

 

MAF codes are generally set by a faulty MAF sensor, vacuum leak, faulty PCV valve, open or short in MAF sensor wiring harness or connector.

 

First, check for vacuum leaks, including the intake manifold and throttle body. Spray around base of intake manifold with carb cleaner while engine is idling. If idle changes, replace intake manifold gasket.

 

If no leaks, then perform the following tests to determine whether MAF sensor is bad, or a wiring issue:

graphic

 

Click to open and download> Fuel pressure test

 

Eric and 5 other Chevy Specialists are ready to help you
Customer: replied 8 years ago.
Thanx Eric,
I know what to do now... time to get to work! Wink --- Peace,Customerbr />