P0300 code

[teamgreen]

Alright mechanically inclined people, I could use a little help with a 2004 Silverado 6.0L gasser

P0300 Random Misfire Detected;

Fuel Sys 1 CL
Fuel Sys 2 CL
Calc Load % 2.75
ECT (C) 62
STFT B1 % 0.78
LTFT B1 % 0.78
STFT B2 % 51.56
LTFT B % 0.78
MAP (kPa) 40.00
Eng RPM 622
MAF (g/s) 8.00
TPS % 11.37

Please read my whole story here

Please Help! - GM-Trucks.com

 

[Summitric]

alright mechanically inclined people, i could use a little help with a 2004 silverado 6.0l gasser

p0300 random misfire detected;

fuel sys 1 cl
fuel sys 2 cl
calc load % 2.75
ect (c) 62
stft b1 % 0.78
ltft b1 % 0.78
stft b2 % 51.56
ltft b % 0.78
map (kpa) 40.00
eng rpm 622
maf (g/s) 8.00
tps % 11.37

please read my whole story here

please help! - gm-trucks.com

hmmmm. Good luck. When's last tune-up? Wires? Injector flush?..... Your computer has picked up random cylinder misfire, and could be 1 or more, of about 100 different problems... Intake vacuum leak? I see the tps reading is too high, but was this printed at idle? Also the map reading(what is that in psi?) .... Keep us posted.

 

[teamgreen]

MAP is at about 6 psi, sprayed carb cleaner around the manifold but didnt make a difference in RPM. Was printed at idle. Hasnt been tuned up since I bought it 18 months and 80 000km ago

 

[Familyfun]

Short term fuel trim is how much fuel is being added currently to that bank. Most likely needs an o2 sensor. Can you watch data in real time?

 

[growly]

Weak Fuel pump or clogged filter will throw lean codes.So is the truck puking black smoke and going through a tank in 200k again?

You said in the other forum........and I quote.......

The Fuel filter is in the tank of the truck. Air Filter is brand new and I cleaned the Maf with sensor cleaner. Fort McMurray is terrible for putting everything in tanker trucks, I was at a station there once and the guy was filling the tanks and he still had placards on the truck from when he was carrying molten sulphur. He said he had only residue left than filled the truck full of gas. Just found it weird that when I start it, it seems to run okay for 30-45 seconds than starts to misfire.

How can I check fuel pressure?


It's not fuel,just had a similar 1 come through the shop. If you can look at data in real time you will find you have a bad O2,the B1 sensors should switch between 100-800 give or take @ 2500 rpm.The 1 in the shop,B1 stayed at 40 and all of B1 had misfires.


Yours runs fine for 30-45 seconds because it isn't using O2 values till the sensors warm up.

 

[teamgreen]

my code reader doesnt do real time, I guess if I take it to a shop they can do that than know its the 02 sensor and just replace it. Ive been reading other places that it could be cats, coil packs, wires etc etc. and I dont have the time or money to just start changing stuff.

Can I switch the bank 1 and bank 2 02 sensors and see if it just does the same thing but on the other side?

 

[Ancient Sledder]

With your short term fuel over 50% it has to have an intake leak. I am an Import tech and have not worked on a pick-up for 10 years. The last leak I found, I took off the air intake tube to the manifold and with the engine running I just put my hand over the throttle body. If it dies, the intake gaskets are good. If it still runs, it's sucking air from some place it's not supposed to. Good Luck and I hope it's a cheap fix.

 

[teamgreen]

Did another scan and came up with this info:

Fuel Sys 1 CL
Fuel Sys 2 CL
Calc Load % 34.90
ECT (C) 93
STFT B1 % 3.91
LTFT B1 % 9.38
STFT B2 % 55.47
LTFT B % 9.38
MAP (kPa) 84.00
Eng RPM 2372
MAF (g/s) 89.00
TPS % 43.53

Can't seem to figure it out so I guess it goes to the shop in the morning, hopefully its fixed for the weekend sled trip