My truck has become a gasoholic

Okay, so yesterday my ma needed to use my truck and went an hour away somewhere (don't ask, I was seriously half asleep when she explained what she was doing. Something about taking the dog to the vet). Anyway, upon returning home she complained about how much of a pig the Ram was and that it used about twice as much fuel as her Silverado would have used. At first, I thought that was just an exaggeration since we all know second gen Rams miser their gas like an alcoholic misers their booze but nonetheless I decided to actually take note of my fuel consumption. I made a 40-mile all-highway trip this morning and my jaw dropped to see that I burned about 3/16 of a tank! That translates to something under 10 MPG whereas I was getting 12 even. What's strange is that the truck runs and drives perfect, except for the really aggravating cold-start issue that resurfaced when the lows started dropping into the low teens again (mother****er!).

So, my fuel economy has gone from bad (normal) to atrocious (not normal) and the engine has all the power that it had before which is pretty unusual for an engine that's suddenly burning like 50% more gas than before. No CEL. I'm gonna grab my scanner later and run a live data scan to look for anything odd. Y'all have been very helpful in the past, so I turn to you again for suggestions as to what to look for.

Again, engine runs the same as it has before, but suddenly uses significantly more gas. Christ, I sure hope that I'm not just imagining things. I filled the tank after my drive but totally forgot to reset the trip meter. I'll run the ole' fashioned fuel economy test later if I don't find anything obvious.

Oh, and I did check for fuel leaks. Didn't find anything.

Yeah get an accurate reading of current mileage and get back to us. Honestly, yours sounds fairly close to mine lol

I usally fill my tank to the top, then I go for the drive and then top up again to see how many litres I used. Also don,t forget to reset the meter before.

What plugs are you running and when did you change them last?

I have an 03 QCSB with the 5.9. Under 100k on it. Got 10 mpg when I bought it December 2015. Last year did a plenum, full tune up (cap, rotors, plugs, wires, drop in K&N) saw no difference in MPG. Few months ago did O2 sensors hoping it would help. NOPE, still in the 10mpg range. Probably gonna sell it for a truck that gets better wven though I love it. No CEL, tranny shifts fine. I am stumped why it is so crappy.

My brother had a 95 F250 with a 351 and a C6 tranny WITHOUT overdrive and it got 10mpg also. I Know it should get better than it does.

I had a 2001 Jeep Cherokee and overnight MPG dropped from 16 to 13 for no reason. (There was an inexplained reason - I remoted started it, walked up to it and fuel was POURING out of the fuel filler neck with the fuel cap on. NOBODY has been able to explain the fuel poring out other than the obvious "the fuel tank must have been pressurized"

I am gonna follow this thread to see if you find anything out.


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07MegaCabRam said:

What plugs are you running and when did you change them last?

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Champion RC12YC. Changed them last summer and recorded 12 MPG following my tune.

Pops threw an obvious check for me to do. Pull a few plugs and note the color. Sure, if the engine's running rich, the plugs will show it. I'll do that before going for a little cruise after filling my tank again and record my mileage.

My next plug change, which will be later this year, maybe sooner depending on things, I'm gonna try NGK BKR6E because that's what Ryan suggests while using his tune on a bolt-on'd 360.

Pulled a couple plugs. They look absolutely perfect with totally clean insulators with a light brownish "coat" on the firing tip and ground strap.

Engine started first try without even the slightest hitch. Hell, even my coolant leak which appears to be at the heater hose inlet didn't even appear. In fact, the puddle of coolant that had formed receded to almost nothing. Today was mid 50s.

I'm honestly just gonna cast rationale to the wind and just say that my engine simply just doesn't like cold weather, LOL. I haven't gone for a drive yet to verify fuel economy (too much cheap beer this weekend. Milwaukee's Best Ice = stick your brain in a microwave). I'll check that out as I drive to and from work this week though honestly I wouldn't be surprised if my fuel economy didn't "fix" itself too.

I swear, sometimes I think that my truck just screws with me for fun...

Is this highway driving. Maybe it's not getting into o/d. The transmissions aren't great. And the torque converters aren't anything to brag about either. Mine won't go into od but doesn't always give me the 1740 code.

I assume you live in a cold claimant, you will get your 12 MPG back in a month or so , I take a 2 MPG hit in the winter as well

Sterling said:

Is this highway driving. Maybe it's not getting into o/d. The transmissions aren't great. And the torque converters aren't anything to brag about either. Mine won't go into od but doesn't always give me the 1740 code.

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I've had a permanent P1740 code since i got the truck 5 years ago and my lockup has basically ceased to exist. Still have all gears just no lockup lol.

Oh she shifts into OD just fine. Cruises 70 at something like 1,900 RPM, though more commonly cruises 2,100 at 75. I can't help if the engine feels more comfortable at 75 than 70, LOL.

Witch: Cold climate? Eastern Iowa. 'nuff said, LOL.

Pepper: So, you gonna rebuild the tranny before boosting the engine or gonna boost the engine first and see how long it'll hold till it blows up?

Yeret said:

Oh she shifts into OD just fine. Cruises 70 at something like 1,900 RPM, though more commonly cruises 2,100 at 75. I can't help if the engine feels more comfortable at 75 than 70, LOL.

Witch: Cold climate? Eastern Iowa. 'nuff said, LOL.

Pepper: So, you gonna rebuild the tranny before boosting the engine or gonna boost the engine first and see how long it'll hold till it blows up?

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Getting the new trans this spring. Just need time and money to have somebody swap it. Don't have the room or tools to do it myself

http://www.ramforum.com/f61/gas_mileage_plummets-62089/

Still runs great but 7 MPG in the winter.