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P0300

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Old November 3rd, 2019, 10:15 AM
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Hello all. Having issues with my 99 tahoe 4x4 2door v8 350. I'm having a P0300 code. cylinders 4,5,6, & 7 are misfiring. changed all spark plugs, spark plug wires, distributor cap and rotor, new coil, new ignition control module, new MAF, new O2 sensors, new Crankshaft position sensor, new fuel filter, and IAC. I have spark on all plugs. I get proper voltages in all areas. The only thing I can think of is the spider assembly has gone bad. it has the new MPFI system installed a few years ago. New Fuel pump was installed 1 year ago. Any ideas what can still cause this?
Old November 3rd, 2019, 12:28 PM
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You might get better answers from fellow owners in the Tahoe section. I would suggest testing the fuel injectors, and compression testing the misfiring cylinders.
Old November 5th, 2019, 5:03 AM
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Originally Posted by machete166
Hello all. Having issues with my 99 tahoe 4x4 2door v8 350. I'm having a P0300 code. cylinders 4,5,6, & 7 are misfiring. changed all spark plugs, spark plug wires, distributor cap and rotor, new coil, new ignition control module, new MAF, new O2 sensors, new Crankshaft position sensor, new fuel filter, and IAC. I have spark on all plugs. I get proper voltages in all areas. Visit Autofthings to review headlight clear coat if you concern. The only thing I can think of is the spider assembly has gone bad. it has the new MPFI system installed a few years ago. New Fuel pump was installed 1 year ago. Any ideas what can still cause this?
I think you should check all plug wires that are correct plug and tight.
Old November 8th, 2019, 7:05 AM
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Could be an intake leak of some sort. Spider injection can go bad, or using cheap fuel, which wont keep the injectors clean.
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