Dtc P0300 Random Misfire At Highway Speeds

[dojake]

[font="Times New Roman"][size=3][/size][/font][size=3][font="Calibri"]Hope this might help someone; I have a 2002 Chevy Silverado2500 HD with 6.0 Vortex engine about 65K miles that was throwing a DTC-P0300 (Random Misfire) codewhen it was driven above 60-70 MPH. I wasable to borrow a Tech 2 Scanner to get the Cylinder Misfire Count history.Cylinders 1,5,6,8 had the miss fires. After doing some Checking, determined theCrankshaft positioning Sensor (located behind the starter) had heavy rustbuildup between the engine block and shoulder on Crankshaft Positioning Sensor.The rust pushed the sensor out enough to change the gap between sensor andCrank which affected the pick at high speed. The problem was resolved by removingsensor, cleaned rust build up from the face (don’t damage bore and keep rustout of hole) then installed new sensor (had one on hand), problem was solved. Noteyou need to relearn the Crank shaft Position sensor using a Scan tool with thisfunction available. I have read some people have put big bucks into problemsthat sound similar to this, hope it saves someone time and money![/font][/size]

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