allright so my 04' QC 2500 hemi 4x4 has about 115K on it now, every so often in the past if i let my truck sit for more than 2-3 days it would run like crap the first time i started it until it warmed up then ran fine..

i let it sit for about 8 days (out of town) and now every time i start it it has a BAD misfire all the way up to about 75% throttle then runs like a bat outta hell..im not quite sure in which direction i should go with this..i was thinking of having the injectors rebuilt or buying low mileage 6.1 injectors (if it would be any better..) but i dont want to go ahead and do this without pin pointing the problem IE if i have bad coils or somthings wrong with my throttle body..ect..

so i bought an obd2 blue tooth adapter and downloaded the Torque app for android to maybe help and ive got a couple questions..

1. is my O2 sensor voltage supposed to jump around or kinda stay within the same area?

2. would it be detrimental if my fuel trim is completely opposite for both banks?

3. would an evap leak cause any of this? ( i dont really think so but ill give it a shot)

and 4. what does a QC 2500 4x4 hemi weigh? GVWR is 8800 but thats loaded to capacity right?

thanks for any help!

 

So I've noticed that when I first start my truck..the left bank runs really lean and that's when its missing, it keeps leaning out til it gets to minus 15 and stays there till I rev the truck..then it runs fine

 

I had the same exact problem. Kept throwing a po300. I hooked up my scanner and watched the voltage drop out of my upstream bank 1 o2 sensor when I gave it some throttle. I replaced both upsteam o2 sensors and it took care of the problem.

 

Ill have to check this afternoon, but I think my upstream o2 sensors stay within reason..its the fuel trim on bank 1 thats dropping like crazy

 

The updraft o2 sensors were the culprit..hard time getting them out but sure am glad that was the problem..

still can't fine evap leak..could having the oil vent hooked up to a filter instead of the intake cause the code?