Hey every body I’ve got a 01 Silverado 2500 6.0l. About a month and a half ago give or take, it would out of no where develop a miss on cylinder 3. I swapped out a coil pack and wire from another cylinder that’s never missed and it doesnt change a bit. When it would start missing I could pull over pop the hood take cylinder 1 plug wire off the plug while running and let it arc on a random stud that’s on the engine and the miss would go away. Sometimes it can kick it down and the miss would stop or just take it easy and eventually it’ll go away. I’m thinking maybe a ground issue? Hopefully yall can lead me in the right direction cause it’s getting pretty annoying.
Random misfire
- Thread starter Dylan2234
- Start date
flyboy2610
Member
Not very old. It’s not the plugs. I pulled the wire off and put a screw driver in the wire and grabbed it and it didn’t light me up . Didn’t have any spark at all coming from the coil.
Welcome to GMT Nation...
Even though your Truck is a year behind the listing of the vehicles involved in THIS TSB PDF... The Diagnostic Information explained will prove invaluable when the conventional approaches with Changing Out the Coil Over Plug and Spark Plug or even replacing the #3 Cylinder EFI have been tried and yet, the Misfire Problem remains persistent.
In addition to what follows... just know that by allowing the Spark Plug Wire to discharge OUTSIDE of the compression events present INSIDE the cylinder... without the natural In-Cylinder impediments created by the chemistry of poor (or LEAN) combustion from Low Compression being present, the Misfire Plug-Wire symptom might seem to subside. Bench Testing the Suspect COP seems in order from what you have already discovered.
The reaction of the COP to In-Cylinder LEAN Conditions caused either by a Failing or Poorly Performing Fuel Pump, a Failing or Clogged EFI or an Unregulated Vacuum Leak somewhere around the Intake Manifold will presage many Misfires that can be very hard to run to ground. The Vacuum Leaks can often be detected by lightly spraying 'Starting Fluid' all around the perimeter of the Intake Manifold Flanges with the Engine at Idle and then listening for the Engine RPM to INCREASE. Use CAUTION and Keep an ABC Fire Extinguisher at hand when performing this Test... and Do NOT Do So with the Vehicle INSIDE of any closed spaces or a Garage.
Performing a Dry-Wet Compression Test on the Cylinder Bank involved might also prove that you have Poor or Worn Valve Seating in either an Intake or an Exhaust Valve resulting in Too Low of a Compression Level to effectively support Ignition and Combustion. In any case... Read this PDF and widen your gaze for what is suggested herein.
Adding an Oscilloscope to your Test Equipment Regimen for the Diagnostics of the COPs, the EFIs, the Fuel Pump Performance, and Relative Compression Test during Cold Cranking will also provide more definitive data about what is actually going on INSIDE of the Motor while it is RUNNING as well. For more information on how these "O"Scope Tests can be done (most of which are Completely Non-Invasive and relatively easy to conduct) ...please drop in on THIS link below:
gmtnation.com
One Last Suggestion...
Mice and other Rodents can "Set Up Shop" under the hood of warm engines as the Sun sets in colder climes...and leave behind artifacts of their "GNEED TO GNAW" upon Plastic Wire Harnessing and Connectors and once chewed through, the Copper will quickly corrode to a Green Powder or with badly chewed wires... cause Intermittent electrical problems. Look over everything under the Hood with a Bright Flashlight... in particular looking for signs of Nesting or a Greasy Black residue and signs of Dried Urine and Feces.
Be advised that if present and left there by the North American Deer Mouse... they are carriers of the Dreaded HANTA Virus that if inhaled, causes 40% of those infected ...to DIE (There are NO Effective Treatments or Cures for HPS - The Hanta Pulmonary Syndrome) after presenting with symptoms very similar to the Covid-19 Viral Variants.
Wear Eye Protection, an N-95 Face Mask and M11 Nitrile Gloves. Use ONLY WET Cloths soaked in Bleach mixed in Warm Water to clean surfaces and USE NO COMPRESSED AIR to blow out those infected or dirty under-hood locations as the HANTA Virus is Transmitted on Dirt Particles that can become airborne if agitated and then become inhaled into the Lungs, and Mouth:
Visit THIS Link for more Data On HANTA Virus Infections:
Even though your Truck is a year behind the listing of the vehicles involved in THIS TSB PDF... The Diagnostic Information explained will prove invaluable when the conventional approaches with Changing Out the Coil Over Plug and Spark Plug or even replacing the #3 Cylinder EFI have been tried and yet, the Misfire Problem remains persistent.
In addition to what follows... just know that by allowing the Spark Plug Wire to discharge OUTSIDE of the compression events present INSIDE the cylinder... without the natural In-Cylinder impediments created by the chemistry of poor (or LEAN) combustion from Low Compression being present, the Misfire Plug-Wire symptom might seem to subside. Bench Testing the Suspect COP seems in order from what you have already discovered.
The reaction of the COP to In-Cylinder LEAN Conditions caused either by a Failing or Poorly Performing Fuel Pump, a Failing or Clogged EFI or an Unregulated Vacuum Leak somewhere around the Intake Manifold will presage many Misfires that can be very hard to run to ground. The Vacuum Leaks can often be detected by lightly spraying 'Starting Fluid' all around the perimeter of the Intake Manifold Flanges with the Engine at Idle and then listening for the Engine RPM to INCREASE. Use CAUTION and Keep an ABC Fire Extinguisher at hand when performing this Test... and Do NOT Do So with the Vehicle INSIDE of any closed spaces or a Garage.
Performing a Dry-Wet Compression Test on the Cylinder Bank involved might also prove that you have Poor or Worn Valve Seating in either an Intake or an Exhaust Valve resulting in Too Low of a Compression Level to effectively support Ignition and Combustion. In any case... Read this PDF and widen your gaze for what is suggested herein.
Adding an Oscilloscope to your Test Equipment Regimen for the Diagnostics of the COPs, the EFIs, the Fuel Pump Performance, and Relative Compression Test during Cold Cranking will also provide more definitive data about what is actually going on INSIDE of the Motor while it is RUNNING as well. For more information on how these "O"Scope Tests can be done (most of which are Completely Non-Invasive and relatively easy to conduct) ...please drop in on THIS link below:
How To Use PICO #2204A & HANTEK #1008C Oscilloscopes
You don't need a Huge Bag of Coins in order to obtain and use an Oscilloscope for performing In-Depth Wave Form Analysis in Automotive Applications on everything from Problematic Electronic Fuel Injection to obtaining accurate Compression Tests to Diagnose Internal Engine Conditions. HANTEK...
gmtnation.com
One Last Suggestion...
Mice and other Rodents can "Set Up Shop" under the hood of warm engines as the Sun sets in colder climes...and leave behind artifacts of their "GNEED TO GNAW" upon Plastic Wire Harnessing and Connectors and once chewed through, the Copper will quickly corrode to a Green Powder or with badly chewed wires... cause Intermittent electrical problems. Look over everything under the Hood with a Bright Flashlight... in particular looking for signs of Nesting or a Greasy Black residue and signs of Dried Urine and Feces.
Be advised that if present and left there by the North American Deer Mouse... they are carriers of the Dreaded HANTA Virus that if inhaled, causes 40% of those infected ...to DIE (There are NO Effective Treatments or Cures for HPS - The Hanta Pulmonary Syndrome) after presenting with symptoms very similar to the Covid-19 Viral Variants.
Wear Eye Protection, an N-95 Face Mask and M11 Nitrile Gloves. Use ONLY WET Cloths soaked in Bleach mixed in Warm Water to clean surfaces and USE NO COMPRESSED AIR to blow out those infected or dirty under-hood locations as the HANTA Virus is Transmitted on Dirt Particles that can become airborne if agitated and then become inhaled into the Lungs, and Mouth:
Visit THIS Link for more Data On HANTA Virus Infections:
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