This is topic non ford gmc sierra p0300 code in forum Tech Talk at Northern California Ford Owners  .


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Posted by NvrGoFullRetard (Member # 1633) on :
 
posted on other forum. i have a 2003 gmc sierra 6.0 and i was getting a blinking engine light. it was a pre dtc code random misfire cylinder #1.
i changed the plugs with the factory ac delco spec plugs and wires. still no change. i then changed the coil pack on cylinder 1 and now i have a p0300 code and runs rough. any input would be appriciated.
 
Posted by 5.0 LsX (Member # 10017) on :
 
•Faulty spark plugs or wires
•Faulty coil (pack)
•Faulty oxygen sensor(s)
•Faulty fuel injector(s)
•Burned exhaust valve
•Faulty catalytic converter(s)
•Stuck/blocked/leaking EGR valve / passages
•Faulty camshaft position sensor
•Defective computer

just keep going down the list...double check ground wires too
 
Posted by NvrGoFullRetard (Member # 1633) on :
 
I replaced so far,
Plugs
Wires
Coil packs
I have an extra set of fuel injectors and o2 sensors i can try.
 
Posted by Venomousnotch (Member # 8695) on :
 
Code: P0300
Description: Random/multiple cylinder(s) - misfire detected
Specification: Spark plug(s), HT lead(s), injector(s), ignition coil(s), low compression, wiring....Have you checked and made sure all your injectors have pulse...The last truck I worked on with this code PO300 ended up being the injectors were not spraying properly.. [patriot]
 
Posted by NvrGoFullRetard (Member # 1633) on :
 
No i dont havethe proper equipment to check these. But i have extra parts laying around. This weekend i'll try to check it out this werkend
 
Posted by Kb69fastback (Member # 13054) on :
 
Catalytic converters do this on chevy and gm from 99-07. We do them a lot at my shop. They will throw random misfire codes. No matter how many parts you throw at it, it never changed

It always starts with p0301

The cats get clogged and back pressure to the engine and causes the o2 sensors to go crazy

Usually cats go bad from faulty o2 sensors as well

We use a modis and check for misfire on each cylinder.

We Check numbers on o2 sensors and make sure the numbers and switching correctly

We also check all the injectors for misfires as well

Before you blow anymore money. Go to a muffler shop and just ask for a simple back pressure test. They will put a o2 sensor out and put in a back pressure tester and start the car to see of they're clogged
 




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