P0300 - Random Misfire

AF_Hemi · Aug 12, 2010

Help me troubleshoot. Gettin a P0300 code for Random Misfire Detected.

For some reason it seems like the truck is erasing the PCM when the truck is off for a while. I can start the truck fine, but it idles real shaky and tries to stall until i get about 15 miles on it when the pcm learns the tune again. Twice now its actually stalled coming up to a stop sign -- something its never done before.

Any ideas?

KGBIGCOUNTRY · Aug 12, 2010

Have you checked the battery? You could be loosing some charge on it then it when its running the alt is bringing it back after a few? That could poss explain the computer acting ******** till it runs for a few? Just tossing out an idea.

AF_Hemi · Aug 12, 2010

nope. pcm takes very little power. starting the truck takes way more. I'm not losing any juice on the battery either.

KGBIGCOUNTRY · Aug 12, 2010

PCM takes a constant 12 volt supply, is Marty still around to ask?

AF_Hemi · Aug 12, 2010

nope he's deployed. Its not about volts. Using that argument a 10,000w sound system uses the same power as an LED. true they both use 12v, but its the amperage draw that makes the difference.

I've read other places that a P0300 is normal with a cam. Not sure why, but apparently its nothing to worry about. I just wonder why its just not popping up when i've had the cam in for several months

ramhunter9 · Aug 12, 2010

sounds like you need a new CTD megacab on 40's .

AF_Hemi · Aug 12, 2010

dont freaking tempt me. i just got promoted which comes with an extra $1500 a month. im trying to do the responsible thing and get completely debt free in 2 yrs. comments like that make it tough

ramhunter9 · Aug 12, 2010

CTD rollin on 40's....ohhh awwww

KGBIGCOUNTRY · Aug 12, 2010

So I am corrected, if I get a P0300 misfire with my new setup I will let you know.

KGBIGCOUNTRY · Aug 12, 2010

A_F what ended up with Chefferds truck when he ran into that recently? Yall are both using DSPs I believe maybe its something simple I cant remember much about his last problem other then the random misfire also.

03MopaRamman · Aug 12, 2010

Is your intake leakin anywhere, Just a thought!

AF_Hemi · Aug 12, 2010

not sure. i dont think so, but what would that matter? learn me

harleyowners0709 · Nov 24, 2011

yes i just went though the same thing my mech.found a broken valve spring on cyl.num one they are noted for them he said

03MopaRamman · Nov 25, 2011

Sorry to hear about your spring breakage but a P300 Random...Hmmm....thats odd.
Got one the other day after a WOT run while doing a fuel injector cleaner Tank of Fuel and tends to do that just before or during the cleaning process. On a newer Tank of Fuel now and everything seems good/bsck to normal. Did some 80 mph 2500 RPM overdrive runs on the Hwy. If it comes back I will pay and get The Caustic $189 Solution Hooked into my Fuel Rails as I got 244,000 km anyhow and have never had them professionally cleaned as other folks usually don't touch my Truck unless its Tires, alignement, or exhaust.

KGBIGCOUNTRY · Nov 26, 2011

Blast from the past here, the random misfire code is a side effect of some cams is what is claimed... neither of my two cams tossed that code, that being said its possible the tune was slightly off on timing. That KRC cam had alot of quirks.

OlDirtyJohn · Nov 26, 2011

03MopaRamman said:
Sorry to hear about your spring breakage but a P300 Random...Hmmm....thats odd.
Got one the other day after a WOT run while doing a fuel injector cleaner Tank of Fuel and tends to do that just before or during the cleaning process. On a newer Tank of Fuel now and everything seems good/bsck to normal. Did some 80 mph 2500 RPM overdrive runs on the Hwy. If it comes back I will pay and get The Caustic $189 Solution Hooked into my Fuel Rails as I got 244,000 km anyhow and have never had them professionally cleaned as other folks usually don't touch my Truck unless its Tires, alignement, or exhaust.

i usually just take the fuel rail off, pop the injectors out, and clean them by hand. its not a bad process at all. rather easy actually.

P0300 - Random Misfire

AF_Hemi

Senior Member

KGBIGCOUNTRY

Senior Member

AF_Hemi

Senior Member

KGBIGCOUNTRY

Senior Member

AF_Hemi

Senior Member

ramhunter9

Senior Member

AF_Hemi

Senior Member

ramhunter9

Senior Member

KGBIGCOUNTRY

Senior Member

KGBIGCOUNTRY

Senior Member

03MopaRamman

RAM SPORT / 18 SRT

AF_Hemi

Senior Member

harleyowners0709

Junior Member

03MopaRamman

RAM SPORT / 18 SRT

KGBIGCOUNTRY

Senior Member

OlDirtyJohn

Senior Member

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