 
				
	| 2000 GMC 3500HD 7.4L Misfire Engine idles fine and will rev fine if you give it just a little throttle. Try to give it a heavy throttle and the engine starts missing, if the throttle is held steady at any RPM the engine runs smooth with no miss but as soon as you try to give it some throt... 
                        
                            FIX posted 2/1/2010
                               
                    iATN Members:  Login to view full TechHelp request Auto Repair Pros: Join iATN to read this TechHelp request Vehicle Owners: Find a nearby iATN member to repair your vehicle 9 Replies Received (View Replies)9 Replies Received (Hide Replies) | Message Closed w/FIX 
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| VIN | 1GDKC34J5Y | 
| Engine | 7.4 L / 8 cyl | 
| Delivery | Fuel Injection | 
| Emissions | OBD-II Compliant | 
| Symptoms | Misfire | 
| Occurs | On Accel | 
| Misc. | California Emissions W/O Smog Pump | 
Trouble Codes
| P0131 | Heated Oxygen Sensor (Bank 1 Sensor 1) Circuit Low Voltage | 
| P0134 | Air Fuel Sensor (Bank 1 Sensor 1) Heater System Malfunction | 
| P0135 | Heated Oxygen Sensor (Bank 1 Sensor 1) Heater Circuit Malfunction | 
| P0154 | Air Fuel Sensor (Bank 2 Sensor 1) Heater Circuit Malfunction | 
| P0155 | Heated Oxygen Sensor (Bank 2 Sensor 1) Heater Circuit Malfunction | 
| P0171 | Fuel System Too Lean (Bank 1) | 
Message Closed w/FIX
            
             Vehicle Data
 Vehicle Data
                2000 GMC 3500HD
| VIN | 1GDKC34J5Y | 
| Engine | 7.4 L / 8 cyl | 
| Delivery | Fuel Injection | 
| Emissions | OBD-II Compliant | 
| Symptoms | Misfire | 
| Occurs | On Accel | 
| Misc. | California Emissions W/O Smog Pump | 
Trouble Codes
| P0131 | Heated Oxygen Sensor (Bank 1 Sensor 1) Circuit Low Voltage | 
| P0134 | Air Fuel Sensor (Bank 1 Sensor 1) Heater System Malfunction | 
| P0135 | Heated Oxygen Sensor (Bank 1 Sensor 1) Heater Circuit Malfunction | 
| P0154 | Air Fuel Sensor (Bank 2 Sensor 1) Heater Circuit Malfunction | 
| P0155 | Heated Oxygen Sensor (Bank 2 Sensor 1) Heater Circuit Malfunction | 
| P0171 | Fuel System Too Lean (Bank 1) | 
 9 Replies Received
9 Replies Received
 9 Replies Received
          9 Replies Received
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