Need help with p0300

GhostMS3

GhostMS3

Greenie N00B Member
I currently have the corksport Sri and tip, with autotech internals. No AP as yet, so still stock tune.
I changed my plugs about 1000 miles ago to ngk one step colder set to .028. Code came on before the plug change. I also did the spring spring stretch on the coils. Now it is more frequent, and always on cold startupIMG_20190524_194902.jpg IMG_20190524_194909.jpg IMG_20190524_194921.jpg IMG_20190524_194935.jpg
Below are some live data reads from my code reader. This is after a 40 minute drive, at idle. Thanks
IMG_20190524_194902.jpg IMG_20190524_194909.jpg IMG_20190524_194921.jpg
 
How long was the sri on before the misfire code showed? Does the misfire code only come on at cold start and then go away?
 
Rgurleyjr said:
How long was the sri on before the misfire code showed? Does the misfire code only come on at cold start and then go away?
Click to expand...
Maybe a month after the Sri was installed. It comes on at cold start only, but it will stay on unless I clear it with my scanner. If I clear it right after start up, it stays off the rest if the day.
 
I know this pertains more to the crank angle sensor, but try setting your MAF curve below 1.0 volts to 0.
 
I didn't see that.

Also you shouldn't need step colder unless you're modded to high heaven and only running pump gas (no mix). What changed just before this started?
 
Not all sris without tune cause problems. Corksport is factory maf size anyways.

Don't think your intake is causing this. Does it run bad at all? Feel any misfire?
 
If you bypass cold start (by starting the car with the gas pedal pushed in about a half inch and then letting off one the car starts and the rpm shoots up), will it not throw the code?

If so, check for a vac leak to any of the lines running to the intake manifold. I used to throw a random misfire or a cyl 3 misfire on cold starts when the line from pcv to manifold had a little tear in it.
 
Rgurleyjr said:
Not all sris without tune cause problems. Corksport is factory maf size anyways.

Don't think your intake is causing this. Does it run bad at all? Feel any misfire?
Click to expand...
It runs perfectly fine, doesn't feel like I'm getting any backfire. It really is just at startup.

I will try giving a little gas at startup, and see if that helps. I also really need an AP
 
They're unnecessary at his mod level. Especially considering he doesn't have any tuning solution.
 
You want as hot a plug as you can run without detonation to help keep the plugs clean (prevent fouling). Step colder plugs on a full e85 car tends to run like shit in general, as an example (Yeah I know you aren't full corn).

There's a reason the factory plug temp is the way it is.
 
I switched the plugs out Thursday for stock range. Still getting the code, but I'm gonna let it sit for a couple power cycles and see if the ECU resets.
 
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