P0300 Code Help please!
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 19
Likes: 0
P0300 Code Help please!
first off id like to say i had an older post and came back to a ton of great info on tuning and dyno i appreciate everyones expertise .
i have a 03 C5,
full intake
exhaust
headers
tune
small others etc..
i came back in town from being gone a month, crank it runs fine,
go though a strong storm and fill the car up with gum-out fuel conditioner and additive and it throws a p0300 code, I've cleared it and its came back with that and p0306 but that one hasn't returned ..
since then I've replaced the fuel filter, new MSD wires and NGK iridium plugs and it still has no acceleration and exhaust tone is deeper .
it idles okay and I'm still getting a spark from the coils . beginning to get frustrated . any help is welcomed. thank you all!
i have a 03 C5,
full intake
exhaust
headers
tune
small others etc..
i came back in town from being gone a month, crank it runs fine,
go though a strong storm and fill the car up with gum-out fuel conditioner and additive and it throws a p0300 code, I've cleared it and its came back with that and p0306 but that one hasn't returned ..
since then I've replaced the fuel filter, new MSD wires and NGK iridium plugs and it still has no acceleration and exhaust tone is deeper .
it idles okay and I'm still getting a spark from the coils . beginning to get frustrated . any help is welcomed. thank you all!
Melting Slicks
Joined: Aug 2011
Posts: 2,423
Likes: 200
From: Atlanta GA
first off id like to say i had an older post and came back to a ton of great info on tuning and dyno i appreciate everyones expertise .
i have a 03 C5,
full intake
exhaust
headers
tune
small others etc..
i came back in town from being gone a month, crank it runs fine,
go though a strong storm and fill the car up with gum-out fuel conditioner and additive and it throws a p0300 code, I've cleared it and its came back with that and p0306 but that one hasn't returned ..
since then I've replaced the fuel filter, new MSD wires and NGK iridium plugs and it still has no acceleration and exhaust tone is deeper .
it idles okay and I'm still getting a spark from the coils . beginning to get frustrated . any help is welcomed. thank you all!
i have a 03 C5,
full intake
exhaust
headers
tune
small others etc..
i came back in town from being gone a month, crank it runs fine,
go though a strong storm and fill the car up with gum-out fuel conditioner and additive and it throws a p0300 code, I've cleared it and its came back with that and p0306 but that one hasn't returned ..
since then I've replaced the fuel filter, new MSD wires and NGK iridium plugs and it still has no acceleration and exhaust tone is deeper .
it idles okay and I'm still getting a spark from the coils . beginning to get frustrated . any help is welcomed. thank you all!
P0306 indicates cylinder 6 misfire
Normally this is due to low fuel pressure, a vacuum leak, an EGR problem, or low compression. That is where I would start looking.
1. For Fuel Pressure, use a Fuel Pressure gauge to see what the FP Regulator is reading. Should read between 55-65 lbs. 58 is stock.
2. Perform an EGR test. You may be able to do it without a gauge by depressing the value while running and see if the engine speed changes. Make sure it is running at normal operating temp. If the engine speed does not change, replace.
3. Compression Test: You will compression gauge and test each cylinder.
That is where I would start. Here are other possible causes.
4. Faulty Coil
5. Faulty Spark Plugs and/or Wires
6. Camshaft or Crankshaft sensors
7. Ignition module
8. PCM Issues (this could be due to the tune and takes in many different tables AIC, AFR, SPA, etc.). Here is a link to explain.
http://www.megamanual.com/begintuning.htm
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
P0300 indicates multiple cylinder misfires
P0306 indicates cylinder 6 misfire
Normally this is due to low fuel pressure, a vacuum leak, an EGR problem, or low compression. That is where I would start looking.
1. For Fuel Pressure, use a Fuel Pressure gauge to see what the FP Regulator is reading. Should read between 55-65 lbs. 58 is stock.
2. Perform an EGR test. You may be able to do it without a gauge by depressing the value while running and see if the engine speed changes. Make sure it is running at normal operating temp. If the engine speed does not change, replace.
3. Compression Test: You will compression gauge and test each cylinder.
That is where I would start. Here are other possible causes.
4. Faulty Coil
5. Faulty Spark Plugs and/or Wires
6. Camshaft or Crankshaft sensors
7. Ignition module
8. PCM Issues (this could be due to the tune and takes in many different tables AIC, AFR, SPA, etc.). Here is a link to explain.
http://www.megamanual.com/begintuning.htm
P0306 indicates cylinder 6 misfire
Normally this is due to low fuel pressure, a vacuum leak, an EGR problem, or low compression. That is where I would start looking.
1. For Fuel Pressure, use a Fuel Pressure gauge to see what the FP Regulator is reading. Should read between 55-65 lbs. 58 is stock.
2. Perform an EGR test. You may be able to do it without a gauge by depressing the value while running and see if the engine speed changes. Make sure it is running at normal operating temp. If the engine speed does not change, replace.
3. Compression Test: You will compression gauge and test each cylinder.
That is where I would start. Here are other possible causes.
4. Faulty Coil
5. Faulty Spark Plugs and/or Wires
6. Camshaft or Crankshaft sensors
7. Ignition module
8. PCM Issues (this could be due to the tune and takes in many different tables AIC, AFR, SPA, etc.). Here is a link to explain.
http://www.megamanual.com/begintuning.htm
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 19
Likes: 0
very helpful and an idea on where to refocus efforts.. I drove it this morning and the CEL is blinking under acceleration and stays lit when idling .
ill start with a vacuum leak and fuel pressure , sounds the most likely problem. it just doesn't feel mechanical to me it has a pretty hot tune on it now so that's something to look at also .
many thanks guys! ready to have my car back
ill start with a vacuum leak and fuel pressure , sounds the most likely problem. it just doesn't feel mechanical to me it has a pretty hot tune on it now so that's something to look at also .
many thanks guys! ready to have my car back
P0300 indicates multiple cylinder misfires
P0306 indicates cylinder 6 misfire
Normally this is due to low fuel pressure, a vacuum leak, an EGR problem, or low compression. That is where I would start looking.
1. For Fuel Pressure, use a Fuel Pressure gauge to see what the FP Regulator is reading. Should read between 55-65 lbs. 58 is stock.
2. Perform an EGR test. You may be able to do it without a gauge by depressing the value while running and see if the engine speed changes. Make sure it is running at normal operating temp. If the engine speed does not change, replace.
3. Compression Test: You will compression gauge and test each cylinder.
That is where I would start. Here are other possible causes.
4. Faulty Coil
5. Faulty Spark Plugs and/or Wires
6. Camshaft or Crankshaft sensors
7. Ignition module
8. PCM Issues (this could be due to the tune and takes in many different tables AIC, AFR, SPA, etc.). Here is a link to explain.
http://www.megamanual.com/begintuning.htm
P0306 indicates cylinder 6 misfire
Normally this is due to low fuel pressure, a vacuum leak, an EGR problem, or low compression. That is where I would start looking.
1. For Fuel Pressure, use a Fuel Pressure gauge to see what the FP Regulator is reading. Should read between 55-65 lbs. 58 is stock.
2. Perform an EGR test. You may be able to do it without a gauge by depressing the value while running and see if the engine speed changes. Make sure it is running at normal operating temp. If the engine speed does not change, replace.
3. Compression Test: You will compression gauge and test each cylinder.
That is where I would start. Here are other possible causes.
4. Faulty Coil
5. Faulty Spark Plugs and/or Wires
6. Camshaft or Crankshaft sensors
7. Ignition module
8. PCM Issues (this could be due to the tune and takes in many different tables AIC, AFR, SPA, etc.). Here is a link to explain.
http://www.megamanual.com/begintuning.htm
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Le Mans Master
Joined: Jan 2004
Posts: 9,488
Likes: 1,743
From: Knoxville Tn
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
Just throwing this out there but I made a short nitrous pull a few weeks back and I got the flashing CEL. Thought the worst at first lol but after checking the obvious things like plugs and wires etc. turned out the passenger side 02 sensor fried on the inside. It's rare for the 02 sensor causes a misfire but it does happen.
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 19
Likes: 0
passanger 02 sensor is my next, i just now re arranged the coils and still same problem, i also put new gas and no change
also, i pulled the boots off while running to see the spark from the coil and the whole left side of the motor had hardly any engine or rpm attitude change to where when i pulled the boots from the coils on the driver side it drastically changed . don't know if this gives anymore clarity
also, i pulled the boots off while running to see the spark from the coil and the whole left side of the motor had hardly any engine or rpm attitude change to where when i pulled the boots from the coils on the driver side it drastically changed . don't know if this gives anymore clarity
Just throwing this out there but I made a short nitrous pull a few weeks back and I got the flashing CEL. Thought the worst at first lol but after checking the obvious things like plugs and wires etc. turned out the passenger side 02 sensor fried on the inside. It's rare for the 02 sensor causes a misfire but it does happen.
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 19
Likes: 0
did you get any other code than p0300 like any o2 codes?
i was thinking maybe clogged cats too
i was thinking maybe clogged cats too
Just throwing this out there but I made a short nitrous pull a few weeks back and I got the flashing CEL. Thought the worst at first lol but after checking the obvious things like plugs and wires etc. turned out the passenger side 02 sensor fried on the inside. It's rare for the 02 sensor causes a misfire but it does happen.
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
Just like in my case, I had a misfire but no code set for it because of the tune, but the A/F trim readings showed that the problem came from the 02 sensor. I hope this helps.
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 19
Likes: 0
Fixed! After frustration and research I cranked this morning and saw the difference in output from left and right exhaust , cold start and decided to disconnect the cats from the headers and it ran completely fine , no more misfire now just need to decide which cats to go with ! I appreciate everyone's input . I think my tune was running to rich and clogged the stock cats