2006 Dodge Ram 2500 ST 6 speed manual 4x4

My truck seemingly all of a sudden likes to burn more fuel than it ever has. Up until last month I could fill up and easily drive over 600 miles without refueling. Now the distance on a fill-up has dropped about 80 miles. There are no obvious leaks, and the truck still has power. No warning lights on dash. Any thoughts from our resident experts???? Thanks in advance.

 

First place I'd look for the lost fuel is the oil pan. If you had a leaky injector, some of the leaked fuel would burn and some would wash down the cylinder wall and into your oil pan. Look at your oil level. If it is higher than normal, smell it. Does it smell like diesel? Do a paper towel test. Put a drop or two on the middle of a paper towel and let it spread out. Diesel tends to separate and spread further than the oil and you would see the difference (or so I'm told). If there is fuel in your oil, quit driving it. Diesel won't lubricate like oil does and will ruin your engine.

Another possibility is someone nearby with a 5gal can needing some fuel . . .
Sometimes I miss my 6 sp manual. Back to morning brew . . .

 

Thanks for your response. Oil level is at the "full" line - no diesel smell. The watchful eye of the security camera eliminates the possibility of some miscreant trying to sneak off with a few gallons of my diesel. I know where the fuel gauge is supposed to be at 100, 200, and 300 miles. Half full mark used to be 300-330 miles; now it's somewhere in the 270-290 range. At this point we can probably eliminate those 2 possibilities. I'm thankful, but not really surprised, that all injectors seem to be properly injecting. Had an injector fail at 1000 miles on a new 2004 - sounded like a hammer hitting the engine.

6-speed manual keeps me fully engaged in the driving experience.

 

Where do you live at? It might be fuel, fuel supply. Also do you run any fuel addy? I been using Optilube forever, injectors, CP3 love it. (OK, they don't love it,, but i do

 

The fuel mileage is back to normal. The fix was not exactly intended at this time. It also wasn't cheap. A headlight needed fixing.

I had a technician chase down and diagnose why the low beam on driver's side was not working regardless of changing bulb. The diagnosis was a failed fuse box. A couple of grand later all my lights were working, with some working a little differently and some others I had never seen before (bought truck used). Apparently, what it took to fix the headlight also solved the fuel mileage problem. First tank after replacing fuse box calculated to 19.4 mpg, just about average for the way I drive.

I'm lucky they caught the problem before I found myself suddenly driving in the dark some night.

 

Fuse box, electronics and Dodge = headache.