Hi i Have a 2005 chevy 3500 dually dump truck 6.0 gas motor for the past couple of weeks after we had a snow storm i was driving it at low speeds and when i went to give it gas it started kicking out and running really rough barely get over 25- 30 mph with a really rough idle check engine light will flash and throw po300 code If you spray starting fluid down the intake it will clear up I replaced an o2sensor it was calling for seemed to fix for a little while now its back

The messed up part is while you are driving running like crap like a light switch it will clear and run great for how ever long it feels I'm pull my hair out with this thing the list of parts is horrible I've put into this thing to try and fix it

New Fuel Pump
Coil Packs Both Sides
New Wires
Plugs
Coolant temp sensor
Oil Presuure Gauge ( I Needed That )
Crank Sensor and crank relearn
Swaped mass air Flow
New Fuel Rails with injectors
Knock Sensors


And what makes it worse is i can't get it to do it all the time so its hard


Any thoughts Thank you in advance

 

at first, I was going to suggest you test the injectors at their electrical connectors, but I see you replaced them. I know this sounds dumb, but did you replace the fuel filter? also, maybe have the fuel pressure sensor tested. please, test the stuff just don't replace it. been down that road myself!

 

Theres no fuel filter its built into the fuel pump in the tank and do you mean fuel pressure regulator ? if so there isn't one on my year

The only thing i keep going back to is cats but i pulled the front o2s didn't seem to help but idk at this point

 

yes, sorry i meant regulator! Also, are you sure about there being no fuel filter? it is usually located on the frame rail drivers side.

 

ok, a po300 is a random misfire code. I know you have replaced a bunch of parts, but there are a few other things that can cause this. plugs and low fuel pressure are a biggie, but you said you replaced plugs and wires, and fuel pump so we can rule those out. I would still double check to see if there is a fuel filter on the frame rail. Also, you could have a vacuum leak somewhere. check for that by spraying carb cleaner around in there while the engine is running. around the intake manifold and any vac lines and connections. A cold engine is safer, don't want to be spraying flammable liquids on hot parts. ok, there is one other thing I might mention. how old is the battery? I know it sounds crazy, but everything under there needs electricity and even though the battery will start the truck, it may not be good enough to run everything. At least have it tested. anywhere they sell them they should be able to hook a meter up and test them. I hope this helps.

 

Thank you for the help I've done carb cleaner around everything I've checked 3 times for a fuel filter and when i call to order one they say there isn't a listing for one its in the pump and the battery is deff good i keep going back to cats but haven't had time to check it out the only other thing I've heard that i haven't done yet is a cam sensor or a tps but everyone says the tps will throw a code

 

ok, you can go to "troubleshootmyvehicle.com" to see how to test the cam sensor, and HOW TO TEST IGNITION CONTROL MODULES and MASS AIR FLOW SENSORS and MORE. Easy, simple and fast test articles! to see how to test the tps. I would try both these procedures before replacing any more parts.

 

ok I'm going to check it out thank you very much

 

did you ever get a figure it out I am going through this right now with my truck

 

Check the ground for the fuel pump it's all the way in the back on the driver side frame rail it gets Rusty and loses ground