2002 Chevrolet Silverado Service Engine light on

Tiny
TBONE_316
  • MEMBER
  • 2002 CHEVROLET SILVERADO
  • 4.8L
  • V8
  • 2WD
  • AUTOMATIC
  • 165,000 MILES
The service engine soon light is on and when you drive it it begins to blink. When you slow down or at idle it stops blinking and stays on solid. I bought a INNOVA 3020a code reader, of which I wish I had bought another brand and paid a little more. I get a P0300, random misfire the LED indicators show Oxygen sensor and Catalytic converter.
Friday, February 20th, 2015 AT 9:44 AM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,330 POSTS
I don't know what those leds are saying, but the flashing Check Engine light means you're supposed to stop the engine right away, not keep driving it like that. When it's flashing it means too much raw fuel is going into the exhaust system and is going to overheat and damage the catalytic converter. The code 300 would agree with that. Misfires that are spark-related will send unburned fuel and air into the exhaust system. The most likely suspect is spark plugs and wires.
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Wednesday, April 14th, 2021 AT 6:53 PM
Tiny
TBONE_316
  • MEMBER
  • 2 POSTS
I'm in the process of changing the plugs, they have about 40K miles on the the wires were replaced at the same time. The truck has been sitting since I had some health issues.

There was a article on the 2carpros website about a problem with the ground from the ECM to the engine head corroded and causing a P0300. I cannot find it, the only one I see is a braided cable going from a lug on the firewall to the rear of the engine on the drivers side. Can you tell me more about this and reference it to passenger or drivers side front or rear of head.
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Wednesday, April 14th, 2021 AT 6:53 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,330 POSTS
The first thing to suspect with any code 300, random misfires, is worn spark plugs and wires. Most of the time that causes a single-cylinder misfire with the affected cylinder being identified by the code. Since yours aren't that old, the next thing to consider on high-mileage GM vehicles is the injectors.
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Wednesday, April 14th, 2021 AT 6:53 PM

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