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Discussion Starter · #1 ·
Hello All. I did a few searches and didn't find anything that matched my symptoms, so I thought I start a new one. I have a 2005 3.8 Impala (not super charged) with 157k miles on it. It recently started stalling out, cold hot, at idle or highway speeds. No check engine light has come on and my scantool does not find any codes either. What I have noticed a few times is the motor rpm surges at idle when warm, usually less then a couple of minutes then stabilizes to about 600 rpm. Yesterday it stalled at idle, 20 degrees F, and then twice at a drive thru, one window then the next at normal engine temp. It was hard to start at the second window, took about 7 attempts before success. Its totally random. I can drive two days no problems, then it can happen 2 to 4 times in one day.

I replaced the following items.
Fuel Pump (pressure was in range, 57psi)
Fuel Filter
Spark Plugs and Wires

Cleaned or removed any corrosion.
ICM
ICV
Throttle Body
MAF Sensor

Load Tested Battery ( its less then a year old)
Replaced the alternator.

Checked for vacuum leaks on engine (used ether in a few places) nothing found. I checked most wiring and connectors in the engine area.

Any help would be greatly appreciated.
 

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Discussion Starter · #2 ·
Forgot to add a few things

When I can catch the stalling, I notice the inst cluster lights dim.

Also pulled the EGR off a few days ago and cleaned it. I noticed the plunger moved very easily. I could shake it and it would move, or press it and it move move slightly.

Doug
 

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Back in Black
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sounds like you covered most of the stuff. my 2002 3.8 regal was doing the same thing finally after a month set code for MAF cleaned it ran ok for 2day and started again. replaced been good for last 100,000. miles.
Has you gas mileage droped a little, 4/5 mpg? that is what mine did
 

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Yeah, failing MAF or a bad connection to it can cause that, check the pigtail first, MAF isn't a cheap part.
 

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Discussion Starter · #5 ·
Yeah, I have lost MPG, but mostly in the winter and on back roads. I can still get 29 - 30 MPG in the summer on long hauls. I'm looking into how to test it before I blow 170$ on a AC/Delco MAF.
 

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Discussion Starter · #6 ·
I at least was able to throw a code by disconnected the EGR and MAF. So I know the computer system is working.
 

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Discussion Starter · #7 ·
Well you two made a good call. I just replaced the MAF and took a reading of it at idle it's roughly 4.6g/ps and the car will actually start and stay running. Time for a road test. I was not able to get a good reading of the old one, since it was at a point of not running at all. I do not a HZ multimeter so I cannot test for that. For now, I'm happy, since my 2012 Silverado likes to drink a lot, and the Impala isn't such a lush. Thanks!

Oh. alldata says the MAF should be 3-6 g/ps with AC off.

Doug
 
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