p0300 code 03 silverado
03-09-2017, 09:24 PM
#1
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p0300 code 03 silverado
I have a 04 silverado 6.0 swap, while driving it started shaking, the CEL started flashing and now it stayed on. Went to autozone to see the code an it was p0300 random cylinder misfires.. they said it was the fuel pressure regulator, I researched online n it can be a vacum leak, plugs and wires, I checked the plugs n they were good the wires too. Has anybody experienced this before, I dont trust the autozone guys thats why I dont think itd the fuel pressure regulator... Any advise would help.. thanks
03-09-2017, 10:36 PM
#6
my guess is bad cats. i had same problem. once i got over 2500 rpm"s cel started flashing and truck just felt out of breath, just couldn't produce any more power. i cut open my exhaust and found the equivalent of a smashed beer can stuck on a o2 sensor on both banks. yours just might be clogged
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03-09-2017, 11:08 PM
#8
Clogged cats would definitely cause a misfire, have also seen weak coils do what youre describing. Do you have a scan tool you can read misfire data with? If it is truly a random misfire on all or most cylinders or just on one or two cylinders, that would make a big difference in what to look for and where to start... isolated misfires on certain cylinders would be injector, plug or coil! Most or all cylinders would be something more common, ie cats, intake gaskets, low fuel pressure, or a vacuum leak...
03-10-2017, 06:43 PM
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So I drove it to work today but I didn't pass 2k rpms n didn't shake it might be the cats, on my day off ima take them off and look in there see how they look.. if they are bad I'll just buy some lt headers and put them in there