getting bad gas mileage.
 

Hey,

I am getting 12-16 mpg in my 03 Cummins, just over 200k. I have changed the air and fuel filters, put fuel rail cleaner through it, cleaned off the ait and map sensors still got about 3k miles before i need to change the oil and im not getting any fault codes on the obd2. I dont know what to do at this point i do have access to my own obd2 so i need to take readings just let me know. Any help would be appreciated.

Doc89holliay

Please let us know if you have any mods or if the truck is stock.
thanks

Have you lifted or added bigger tires:humm:

Also could be where hes getting his fuel from too.

The truck is bone stock. 2500, 265/70r17 tires. I have changed nothing in the past 6 months but oil and the above items. Thats when i bought the truck

Any light smoke on start up?

none

just wondering if run have run the valves lately. boost leaks will hurt too. to many things like injectors etc to list:hellox:

I dont understand what you mean. Run the valves like just running the engine or what. Are you talking about tracing a fuel leak in the last part or what.

by running the valves i mean check valve lash. the boost leaks i talked about can be intercooler or tubes leaking. injectors can get worn and cause problems too