Please Help!

[CdnFire]

So here is my story:

 

I have a 2004 Silverado 2500 with 6.0 gasser. I drove from Edmonton to Fort McMurray (450kms) without a problem on Thursday. When I got there I put enough gas to go from 1/4 tank to 3/4. Went home and the truck sat til Friday night. It was -35C so Fiday night I went out to start it and warm it up and it wouldnt idle at all, just kept misfiring. I drove it up to the work mechanic shop, checked codes and it only came up at P0300(random misfire)and let it sit inside at room temp til Saturady night. Went in Saturday night and cranked it over and it still wouldnt idle and now the check engine light was not only on but flashing. I drove it to another gas station, topped it right up, added gas line antifreeze and fuel injector cleaner. Later that night I started it up and it ran smoother but still not perfect. I drove back to Edmonton Sunday morning and only got 200km before I was out of gas (DIC said I was getting 6.1 MPG). I twas puking out black crap from the tailpipe and still misfiring Filled it up after that 200km and and added more gas line antifreeze. Filled it up again in another 200km of highway driving when I got to Edmonton. So now Ive run 2 full tanks of gas through it, it isnt idling as bad but still has moments. Drove it this morning after being in my heated garage and it was fine, drove it this afetrnoon and it was acting up again, changed the plugs and no change.

 

I am unsure what to do. Is it a bad batch of gas? plugged cat converter? bad 02 sensors. I cleaned the MAF sensor but made no difference.

 

Please HELP ME

[L29er]

if your 04 has a FF i`d change it, can`t quite remember when they got rid of those babies. may want to check your fuel pressure, could be too high (indicating regulator fault) if there was any snow comming down during your drive i`d check your AF, if it is wet or has and ice in it toss her out...

[norsemanberg]

Talk to the people at the gas station they may have had a driver drop diesel in the gas tank, If they did you will need to pump out the gas in you tank, replace the fuel filter and then fill the fuel tank up with fresh gas from a differant gas station. I have had it happen to my truck and my truck did exactly what yours is, but the gas station owner wouldn't admit that he had diesel in his gas tank

[CdnFire]

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?

[L29er]

It can be scanned or by a pressure tester.

[norsemanberg]

I still think there is diesel in there

[CdnFire]

so I figured out my code reader, here is what it says:

 

Fuel Sys 1 CL

Fuel Sys 2 CL

Calc load % 41.18

ECT © 93

STFT B1 0.78

LTFT B1 8.59

STFT B2 54.69

LTFT B2 8.59

MAP (kPa) 88.00

Eng RPM 2681

MAF (g/s) 106.00

TPS % 54.12

 

So Im assuming there is something wrong in the STFT which I found is short term fuel trim, and I have no idea what it means

[CdnFire]

O2 sensors?

[CdnFire]

so I ran a whole bunch of gas through it, like 6 or 7 tanks and its seems to be running good. Pulled the downstream O2 sensors and cleaned them, bank 2 was covered in crap but bank 1 was clean.

 

Now (3 weeks later)I am getting the code P0430 (Catalyst System efficiency below threshold bank 2), doesn't seem to be lacking power but intermittently throws the code. So that is bank 2 O2 sensor, is there a way of testing the sensor because its like $250 to replace, or could it be that I wore out the catalytic converter due to the huge amount of gas that was being dumped into this side of the motor?

 

I also pulled both downstream 02 sensors again and started the truck, both sides seemed to have the same amount of pressure coming from the 02 sensor holes

 

this is the new freeze frame info:

Fuel Sys 1 OL-Drive

Fuel Sys 2 OL-Drive

Calc Load % 2.35

ECT© 94

STFT B1% 3.13

LTFT B1% -1.56

STFT B2% 3.13

LTFT B2% -1.56

MAP(kPa) 37.00

Eng RPM 568

veh speed km/h 0

MAF (g/s) 6.00

TPS % 9.41

[CdnFire]

So they same thing that originally happened a month ago, did the same thing again, basically the exact same story, I can seem to figure this out, problem went away and now repeated

 

P0300 Random Misfire Detected;

 

Fuel Sys 1 CL

Fuel Sys 2 CL

Calc Load % 2.75

ECT © 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