2000 2500 Sierra 6 .0L Random misfires

I scanned the truck and get a DTC P0300 Random Misfires. So far I changed the sparkplugs, Bank2 Sensor 2 oxygen sensor also had a DTC P0161 code. I also changed the fuel filter. I also added a can of fuel cleane and took it
on a long ride. No difference. I get the misfire once the truck has warmed up and is working hard like going up a slight incline or pulling the fifth wheel trailer. Any suggestions would be appreciated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
try changing the cap and rotor if you dont use a good quality cap and rotor they get moisture in them and they spark all over in side the cap and that might give u a misfire hope this helps
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Umm, if it a 2000 model, I seriously doubt that it has a cap and rotor. I believe it is a distributorless ignition and has a coild to plug set up.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
check your timing marks with a light to see if it is bouncing all over the place.. timing chain may be going.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That might have been useful advice were it not for the fact that nothing in the ignition system is connected to the timing chain.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Come on now, this is coming from the individual that works on newer Chevy's and thinks that Snoturd gives better advice then you do. It HAS to be right information. LOL
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Strangely, Snoqueen has really clammed up on the 94 Blazer thread.
He was -so- sure he had me.
And, as always, he's admitted his screw up (not).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 08 Mar 2007 05:28:33 GMT, aarcuda69062

You assume way too much but your a troll so I am not surprized. Always quick with a smart mouth. If I do not respond the way you think I should it is not because of why you think but rather I just am not going to lower myself they way you do to yourself all the time. I have my theory as to this posters problem but I will let you screw him up. Make sure you list about 5 or 10 things that may be wrong too for big $$$ repair bill. ----------------- TheSnoMan.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Your erroneous answers preclude the need for me to assume anything.

Typical answer from a dumb shit.

Um... You've already answered.

Speaking of 'screw ups,' are you clear now WRT the idling problem on that 94 Blazer and what the possible causes might and might NOT be?

Because vehicle can only have one problem, right? There are no known pattern failures with collateral symptoms on 4.3 Vortec S/T trucks, right?
Ya know, a quick visit to a proctologist could have your head out of your ass in no time.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This time my friend you are very WRONG!!!
His head has been so firmly stuck up his ass for so long, it is doubtful that a team of proctologists using the "jaws of life" and possibly C4 could hope to remove it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Thanks pal. you just gave Snoputz leverage. (wait... no you didn't)

How about that two man slide hammer designed for pulling 4X4 front wheel bearings?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Document ID# 546823 2000 Chevrolet Chevy C Silverado - 2WD
--------------------------------------------------------------------------------
DTC P0300 Engine Misfire Detected Circuit Description The crankshaft position (CKP) sensor is mounted through the side of the engine block at the rear of bank 2 above the starter assembly. The CKP sensor works in conjunction with a 24X reluctor wheel on the crankshaft. The reluctor wheel is inside the engine immediately in front of the rear main bearing. The powertrain control module (PCM) provides a 12 volt power supply to the CKP sensor as well as a ground and a signal circuit.
A misfire causes a change in crankshaft speed. The PCM times the interval between each pulse and compares each new time interval with the previous one in order to determine when an excessive change in crankshaft speed has occurred. You can expect a certain amount of acceleration or deceleration between each firing stroke, but if the crankshaft speed changes are more than an expected amount, the PCM interprets this as a misfire.
The PCM uses the CKP sensor for misfire detection and to control spark and fueling. As the crankshaft rotates, the reluctor wheel teeth interrupt a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this 24X signal in combination with the camshaft position (CMP) sensor 1X signal in order to accurately determine crankshaft position. The PCM also calculates a 4X signal from this information. The PCM uses the 4X signal for internal calculations. The 4X signal also provides a tach signal for any device which requires one.
Observe that as long as the PCM receives the CKP sensor 24X signal, the engine will start. The PCM can determine top dead center for all cylinders by using the CKP sensor 24X signal alone. The CMP sensor 1X signal is used by the PCM to determine if the cylinder at top dead center is on the firing stroke or the exhaust stroke. The system attempts synchronization and looks for an increase in engine speed indicating the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes it incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. A slightly longer cranking time may be a symptom of this condition.
Conditions for Running the DTC No active mass air flow (MAF) DTCs
No active engine coolant temperature (ECT) DTCs
No active throttle position (TP) DTCs
No active crankshaft position (CKP) sensor DTCs
No active camshaft position (CMP) sensor DTCs
No active vehicle speed sensor (VSS) DTCs
The engine speed is between 375 RPM and 5,001 RPM for automatic transmission.
The engine speed is between 450 RPM and 5,001 RPM for manual transmission.
The ignition voltage is between 10 volts and 18 volts.
The ECT is between -7C (19F) and +130C (+266F).
Fuel level more than 10 percent
The TP sensor angle is steady within 1 percent.
The antilock brake system (ABS) and traction control systems are not active.
The transmission is not changing gears.
The secondary air injection (AIR) diagnostic test is not in progress (RPO NC1 only)
The A/C clutch is not changing states.
The PCM is not in fuel shut-off or decel fuel cut-off mode.
The ABS signal is not exceeding rough road thresholds.
Conditions for Setting the DTC The PCM determines that an emission type misfire is present.
The PCM determines that a catalyst damaging misfire is present.
Action Taken When the DTC Sets The PCM illuminates the Malfunction Indicator Lamp (MIL) under the following conditions:
The PCM illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails, if the diagnostic fails under the same conditions such as load, RPM, temperature, etc. as the previous ignition cycle that the test ran and failed.
The first time the diagnostic fails, the PCM records the operating conditions in Failure Records.
The PCM determines the percent of misfire over a 1,000 revolution period is high enough to cause excessive tail pipe emissions. The PCM illuminates the MIL the next consecutive ignition cycle that the diagnostic runs and fails, if the diagnostic fails under the same conditions such as load, RPM, temperature, etc. as the previous ignition cycle that the test ran and failed. Or
The PCM flashes the MIL when the diagnostic runs and fails a catalyst damaging misfire.
Conditions for Clearing the MIL/DTC Important: If the last failure was during a non-typical driving condition, the MIL may remain ON longer than the three ignition cycles. Review the Freeze Frame or Failure Records for the last failure conditions.
The PCM turns the MIL OFF after three consecutive ignition cycles that the diagnostic runs and does not fail within the same conditions that the DTC last failed.
A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
A last test failed clears when the diagnostic runs and does not fail.
Use a scan tool in order to clear the MIL/DTC.
Diagnostic Aids Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
Running the vehicle out of fuel causes sufficient misfire to set DTC P0300. A vehicle that is out of fuel may have fuel level DTCs also set.
Water contamination in the fuel system can cause a single cylinder to misfire as well as cause a random misfire. If there is a misfire in Cylinder #7 it is possible that water has collected in the fuel rail. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
If there is a misfire detected in Cylinder #4or #6 it is possible that the fuel pressure regulator diaphragm has ruptured, causing fuel to be drawn in through the regulator vacuum line. Remove the vacuum line and inspect for fuel contamination.
A restricted fuel filter can cause sufficient misfire to set DTC P0300. Refer to Fuel System Diagnosis .
Excessive vibration from sources other than the engine could cause a misfire DTC. The following are possible sources of vibration:
- Variable thickness brake rotor
- Drive shaft not balanced
- Certain rough road conditions
Observe, if more then one cylinder is misfiring, the scan tool may only display one cylinder misfiring. This will not be apparent until the repair is completed. Also, if an ignition coil ground circuit is open for one side of the engine, the scan tool may only display 2 or 3 cylinders misfiring. Inspect the ground circuit for the ignition coil on the cylinder bank of the engine that has more then one cylinder misfiring.
Test Description The numbers below refer to the step numbers on the diagnostic table.
b.. Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look and listen for arcing or misfiring as you apply the water.
If the Misfire Current counters are incrementing and there is no apparent misfire, an erratic CKP sensor signal could be the cause. Perform the diagnostic table for DTC P0335 first if this condition is suspected.
If a misfire is present and you suspect a fuel control problem, force the fuel system into Open Loop using the scan tool and allow the engine to run for a few minutes. If this eliminates the misfire, refer to any fuel control related DTCs which are set. If no other DTCs are set, refer to the Engine Scan Tool Data List.
A misfire may not be apparent at idle. The misfire may only occur above idle under a load. Road test the vehicle and monitor the misfire current counters.
If more than one cylinder is misfiring, the misfire current counters may only increment for one cylinder. Example: Cylinders 1 and 8 are both misfiring, yet only cylinder 8 increments on the misfire current counter.
If one of the injector fuses is open, only two or three misfire current counters may increment for the corresponding side of the engine.
d.. The cylinder with the more significant misfire may cause another cylinder counter to increment only by a small amount.
j.. If the engine misfire moves with the spark plug, this is good indication that you should replace the spark plug.
l.. An engine mechanical problem can cause a spark plug to gas foul. Inspect for loose rockers, collapsed lifters, or worn camshaft lobes.
q.. If the customer concern is the MIL flashing, this indicates that a Catalyst Misfire has occurred. Drive the vehicle in the conditions to run the catalyst diagnostic.
DTC P0300 - Engine Misfire Detected Step Action Value(s) Yes No
1 Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? -- Go to Step 2 Go to Powertrain On Board Diagnostic (OBD) System Check
2
Important a.. You must perform the CKP System Variation Learn Procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure . b.. If any DTCs are set, refer to those DTCs before proceeding with this diagnostic. c.. If any abnormal engine mechanical noise can be heard, refer to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L.
1.. Install the scan tool. 2.. Idle the engine. 3.. Monitor all the Misfire Current counters on the misfire data list using a scan tool. There are a total of 8 counters, One counter per cylinder. Are any of the Misfire Current counters incrementing? -- Go to Step 4 Go to Step 3
3 1.. Turn ON the ignition, with the engine OFF. 2.. Review the Freeze Frame and Failure Records data for this DTC and observe the parameters. 3.. Turn OFF the ignition for 15 seconds. 4.. Start the engine. 5.. Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in the Freeze Frame and Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC. 6.. Select the Diagnostic Trouble Code (DTC) option, the Specific DTC option, and then enter the DTC number using the scan tool. Does the scan tool indicate that this diagnostic failed this ignition? -- Go to Step 4 Go to Diagnostic Aids
4 Is only one misfire counter incrementing? -- Go to Step 6 Go to Step 5
5 Visually and physically inspect the following items:
a.. Vacuum hoses for splits, kinks, and proper connection -- Refer to Emission Hose Routing Diagram . b.. Throttle body and intake manifold for vacuum leaks c.. Crankcase ventilation valve and/or system for vacuum leaks -- Refer to Crankcase Ventilation System Description . d.. PCM grounds for being clean and secure -- Refer to Ground Distribution Schematics in Wiring Systems. e.. Inspect the ignition coil ground circuit for an open on the cylinders that are showing misfires. An open ground causes all four Ignition Coils to be inoperative. The Misfire current counters only displays 2-3 cylinders misfiring, not all four cylinders. f.. Inspect that all injector harness connectors that are connected to the proper injector g.. Check the injector and ignition control fuses for being open. If you find an open fuse, locate and repair the shorted circuit. Refer to Wiring Repairs in Wiring Systems. h.. Test for incorrect fuel pressure or restricted fuel flow. Refer to Fuel System Diagnosis . i.. Inspect for a restricted exhaust. Refer to Restricted Exhaust in Engine Exhaust. j.. Test for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Diagnosis . k.. If an abnormal engine mechanical noise is heard, refer to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L. Did any of the above checks isolate a condition requiring a repair? -- Go to Step 17 Go to Step 6
6
Important Before disconnecting the injector harness, refer to Fuel Rail Assembly Replacement . There is a special procedure for disconnecting the fuel injector harness connectors.
1.. Turn OFF the ignition. 2.. Disconnect the injector that corresponds to the Misfire Current counters that were incrementing. 3.. Connect the injector J 34730-405 test lamp to the injector electrical connector. 4.. Idle the engine. Is the injector test lamp flashing? -- Go to Step 7 Go to DTC P0200 Injector Control Circuit
7 1.. Turn OFF the ignition. 2.. Reconnect the injector harness electrical connector. 3.. Disconnect the ignition wires from the spark plug that corresponds to the Misfire Current counters that were incrementing. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. 4.. Install the J 26792 spark tester to a ground. 5.. Start the engine. Does the spark jump the tester gap and is the spark consistent? -- Go to Step 9 Go to Step 8
8 1.. Remove the ignition wire for the cylinder that is misfiring. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. 2.. Measure the resistance of the ignition wire using the DMM. Is the ignition wire resistance less than the specified resistance? 700 ohms Go to Electronic Ignition (EI) System Diagnosis Go to Step 16
9 Remove the spark plugs from the cylinder that indicated a misfire. Refer to Spark Plug Replacement in Engine Electrical.
Does the spark plug appear to be OK? -- Go to Step 10 Go to Step 11
10
Important If the Injector Coil Test Procedure checks to be OK, refer to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L.
1.. Swap the suspected spark plug with another cylinder that is operating properly. Refer to Spark Plug Replacement in Engine Electrical. 2.. Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug? -- Go to Step 15 Go to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Between 10-35 Degrees C (50-95 Degrees F)
11 Are the spark plugs oil or coolant fouled? -- Go to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L Go to Step 12
12
Important If the fuel system checks to be OK, refer to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L.
Are the spark plugs gas fouled? -- Go to Fuel System Diagnosis Go to Step 13
13
Important If the Injector Coil Test Procedure checks to be OK, refer to Base Engine Misfire Diagnosis in Engine Mechanical 4.8L, 5.3L, 6.0L.
Do the spark plugs show any signs of being cracked, worn, or improperly gapped? -- Go to Step 14 Go to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Outside 10-35 Degrees C (50-95 Degrees F)
14 Replace or re-gap spark plugs. Refer to Spark Plug Replacement in Engine Electrical. If an improper gap is found, be sure to re-gap spark plugs using a wire type gauge.
Is the action complete? -- Go to Step 17 --
15 Replace the faulty spark plugs. Refer to Spark Plug Wire Harness Replacement in Engine Electrical.
Is the action complete? -- Go to Step 17 --
16 Replace the faulty ignition wires. Refer to Spark Plug Wire Harness Replacement in Engine Electrical.
Is the action complete? -- Go to Step 17 --
17 If the customers concern that the MIL was flashing, were any Catalyst DTC's set? -- Go to DTC P0420 Catalyst System Low Efficiency Bank 1 or DTC P0430 Catalyst System Low Efficiency Bank 2 Go to Step 18
18 1.. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the scan tool. 2.. Idle the engine at the normal operating temperature. 3.. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number using the scan tool. 4.. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable. Does the scan tool indicate that this test ran and passed? -- Go to Step 19 Go to Step 2
19 Select the Capture Info option and the Review Info option using the scan tool.
Does the scan tool display any DTCs that you have not diagnosed? -- Go to the applicable DTC table System OK
--------------------------------------------------------------------------------
Document ID# 546823 2000 Chevrolet Chevy C Silverado - 2WD
Info - Misfire DTCs P0300, P1380, P1381 and Catalytic Converter Damage Due to Installation of Alarm Systems #02-06-05-004b - (02/14/2006)
Information on Engine Misfire MIL/SES Light Illuminated or Flashing DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0420 or P0430 #06-06-04-046 - (09/12/2006)
Due to various factors, the fuel injectors may become restricted. Extensive testing has demonstrated that fuel related issues are the cause of clogged injectors. At this point, no specific fuel, fuel constituent, or engine condition has been identified as causing the restriction. The restriction causes the engine to operate at a lean air fuel ratio. This may either trigger the MIL to illuminate or the engine to develop various driveability symptoms.
Correction Fuel injector restrictions, deposits can be cleaned on the vehicle using the following procedure. Under NO circumstances should this procedure be modified, changed or shortened. As a long term solution, and to prevent reoccurrence, customers should be encouraged to use Top Tier Detergent Gasoline . For further information on Top Tier detergent gasoline and fuel retailers, please refer to the following Corporate Bulletin Numbers:
04-06-04-047G (U.S. Only)
paul

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.