2012 Silverado 5.3 Rough Idle

JC_Reno

Newbie
Original poster
Jan 13, 2022
3
Georgia
Hey all,

I recently picked up a 2012 Silverado 1500 4x4 with a 5.3. I have approx 197k on the truck.I noticed that it has a rough idle, a slight surge at times while on the interstate, it almost stalls out when you start it some days..... it sounds like it had a cam job lol (but not really)

I get an intermittent code for MAF performance, I have sense replaced the MAF for good measure. I've only been running mid grade and premium fuel and even used some fuel system cleaner just in case.

Problem is, it does this all the time but I only get a logged fault for the MAF every now and then with no other accompanying faults. Any insight would be much appreciated.

Thanks,

JC_Reno
 

Mooseman

Master Blaster
Moderator
Dec 4, 2011
21,822
Ottawa, ON
What's the exact code(s) you're getting? If it's still getting a code for the MAF, I would check that there are no leaks between it and the throttle body. Or I'd even check for any vacuum leaks using the carb cleaner. How's the air cleaner?

Have you tried cleaning the throttle body? If you do this, it may need an idle relearn using an advanced scanner.

We're actually going through a similar issue in another thread. The title is almost the same too.

 
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JC_Reno

Newbie
Original poster
Jan 13, 2022
3
Georgia
What's the exact code(s) you're getting? If it's still getting a code for the MAF, I would check that there are no leaks between it and the throttle body. Or I'd even check for any vacuum leaks using the carb cleaner. How's the air cleaner?

Have you tried cleaning the throttle body? If you do this, it may need an idle relearn using an advanced scanner.

We're actually going through a similar issue in another thread. The title is almost the same too.

It has a cold air intake system that was previously installed before I bought it. I have since replaced the filter with a new K&N filter and like I said replaced the MAF sensor. Today I removed the intake plumbing and performed a visual inspection. When I put everything back into place I made sure all of the clamps to the throttle body were tight.

Aside from those few items I have not done much else with it. Trying to keep from just throwing parts at it, that's always been a pet peeve of mine LOL. Thanks Moose, i'll follow the other thread closely as well.
 

Mooseman

Master Blaster
Moderator
Dec 4, 2011
21,822
Ottawa, ON
Those K&N filters are notorious for contaminating MAF sensors and are not recommended. I know you replaced the MAF however, try cleaning it with MAF cleaner. I would also remove that system and find a stock air cleaner from a yard. The performance gain from the K&N is negligible, if any at all.
 
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MRRSM

Lifetime VIP Donor
Oct 22, 2015
5,710
Tampa Bay Area
As an Echo of what @Mooseman has covered for issues that need to be sorted out about any MAF Codes… Paul “Scanner” Danner puts on a Two Part Clinic on “How To Diagnose the GM MAF Sensor and Circuit”. To Cut to the Chase on the Salient Points:

(1) Of the Three Diagnostic Tools that might be used to look into what the MAF is doing… Right or Wrong:

A High End Scanner
A Decent DMM or DVOM
An Oscilloscope

The ONLY Tool capable of rapidly reading the Higher Signal Frequencies and Drop Outs or Power, Ground and Signal Wire Drop Outs produced by the MAF… is an Oscilloscope.

(2) Try side stepping any “Exotic Diagnostics” by looking for something PHYSICALLY WRONG First. You just bought a Stranger’s Truck with fairly High Mileage and have no idea about whether it was driven every day… or left sitting in a parking lot somewhere and attracting 'Rodent Residents' that enjoy Chewing on Wiring Harnesses and Plastic Connectors.

(3) In order to Check Out the MAF Sensor, MAF Sensor Connector and the MAF Sensor Wiring Harnessing for any Breaks or Shorts, Start the Truck and while a “Helper” mashes down on the Gas Pedal to briefly hold it running at around 1,500 to 2,000 RPM… while you:

Gently Press Down on the Outside areas of the MAF Black Plastic Housing.

Slightly attempt to Move the MAF Connector around where it is plugged inside the MAF Sensor.

Perform a MAF Wire Harness “Jiggle” Test.

If the Engine suddenly Stumbles or Dies from any of these actions...look more closely at that Narrow Issue.

(4) Follow the Suggestion made by “Scanner Danner” to use the Point of a Pin Back-Probe and rework the Metal Pin Contacts hidden inside of the Female MAF Connector Ground, Power and Signal Wire locations back to having a better contact surface with each of the Three Internal Male Pins of the MAF. Don’t get Too Enthusiastic or you’ll Damage the MAF Connector. These images illustrate How he did THIS:

SCANNERDANNERMAFPINFIX1.jpgSCANNERDANNERMAFPINFIX2.jpgSCANNERDANNERMAFPINFIX3.jpgSCANNERDANNERMAFPINFIX4.jpg

(5) Watch BOTH of these “Scanner Danner” Student Training Sessions for all of the Fine Grain Details and Step-By-Steps involved for a complete understanding of his Diagnostic approach.

Part 1:


Part 2:


(6) CHECK ALL OF THE GROUNDS FOR THE ENGINE BY USING THIS INFORMATION:


(7) If you want to know more about getting and using inexpensive Hantek or PICO-Scope Oscilloscopes, visit THIS Thread:

 
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