Real bad gas milage, Hemi Ram

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AdamR

AdamR

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I have an 04 2500 Hemi Ram quad cab. I love the truck but man the milage sucks. 8 to 9 MPG lately. I swear it wasnt that bad when I bought it. The truck is pretty much stock, had a Flowmaster cat back and a K&N. I cant see either hurting milage. It doesnt have 373 gears and a limited slip. Anyone else have a 2500 Hemi thats as bad on gas ?
 
AdamR said:
I have an 04 2500 Hemi Ram quad cab. I love the truck but man the milage sucks. 8 to 9 MPG lately. I swear it wasnt that bad when I bought it. The truck is pretty much stock, had a Flowmaster cat back and a K&N. I cant see either hurting milage. It doesnt have 373 gears and a limited slip. Anyone else have a 2500 Hemi thats as bad on gas ?
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You may want to check the O2 sensors, I know when they go bad milage goes right down the toilet!
joe
 
Wouldnt it trip the light though ? How many does it have ? 3, correct ?
 
AdamR said:
Wouldnt it trip the light though ?
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It may or may not trip the light but a trip to Auto Zone to see if there are any codes will verify it.
I dont know how many yours has, I know the jeep wrangler has an upstream and a down stream sensor.
Joe
 
AdamR said:
I think its 2 upstream, one per bank and one down stream.
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Aye, well it may not be it at all but I saw a friends wrangler recently loose the downstream and was getting around 8 to 10 MPG. I would think a light would light if it was bad but have seen stranger things.
joe
 
a clogged cat converter will rob both horsepower and milage. The ecm will adjust mixture , timing etc.., quite far before generating a code or check engine light.
 
The oil from the K&N might have gotten on your mass air flow sensor. If so clean with Electrical Parts Cleaner and let dry before running.
 
A few things to think about Adam... you didnt mention how many miles you have on it, but being a 04 I assume there is a few. First off 95% of the time if a upstream or downsteam 02 sensor is bad it will kick the CE light on. So I dont think thats your problem. Now that being said the 04 Ram 3/4 tons with Hemi never got good fuel mileage... we sold a bunch to farmers and they all came back and bought diesels because they were only getting 10 mpg. Ok..so lets see.... have you had the throttle body cleaned ? have you had a fuel injection flush ? have you replaced spark plugs ? These are things people seem not to do or put off and working here with these trucks every day can tell you.... it makes a difference in mileage. Maybe only 2-3 mpg gain... but that adds up. Check those things if you havnt done them and then recheck.

I anticipate 12-13 mpg would be good. The rumor was the hemi in the 3/4 ton will get just above the v-10 did in mpg..... my V10 only got 8.

check it and see if it helps.

good luck with it.

-RPM
 
In the few years I sold Dodges, the only rear offered in a 2500 or 3500 with a Hemi was a 4.10. You sure it's a 3.73?
 
RPM said:
The rumor was the hemi in the 3/4 ton will get just above the v-10 did in mpg..... my V10 only got 8.
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The best I've ever got with my '95 Ram 2500 V10 was 14mpg empty on a roadtrip. Normal around town/freeway combo is 9-10mpg. That's why my '79 Kawasaki KZ1000 (36mpg) became my daily driver when gas prices went nuts.
 
If you have MDS better make sure you have 5-20wt oil in it or the MDS will not work. This has been the cause of many a Hemi gas problem.
 
The truck has 80K on it. I havent done a thing since I bought it other then change the oil.

Im not expecting much but 12mpg would be nice.

Its not low on power,
The sticker in the glove box says 373 gears,
and it does not have MDS.
 
Adam, I have an 03 Cummings Diesel 2500 automatic, long bed, 4dr,w 4.10 rear. Only thing I added was a K&N Filter and a bed cover. I'm Getting 19.1 MPG. You must have clogged fuel injectors, or the 02's are off. Something is AWRY.. You should be getting like 11-12 IMO. Try a bottle of fuel injector cleaner. Cheap enough. Couldnt hurt.

Eric
 
I would check the spark plugs first as these do not have platinum plugs. Rec changing every 30,000. 12 is about normal for them from what cust say. I believe your truck has 4 o2 sensors, a upstream and a downstream for each bank.
 
should be one off each pipe on each manifold then one at the cat or cats. it wont always send your light off but it may flash trouble codes.
 
Plan on changing 16 spark plugs if not done already. 2 per cylinder. Takes about 2 hours and lots of reaching.
 
wow now i dont feel so bad anymore lol. ive got an 01 ram sport orig a 318 truck priv owner dropped in a crate 360 i get about 9 in town be it idling around or burnin the tires down. but hwy i get 18 to 20 doin 70. but then again its not a stock motor. as far as the O2 sensors go i had one go out that triped a code and set the light off for 2 days then it went off. as for the number of sensors my truck only has 2 though when i went to get the sensor i was told that the Ca models have 3 and states with not so radical smog laws could have 2. good thing my truck came from out of state lol.
 
Service plugs evey 30K, When I did mine it needed it. The plugs right under the coils had alot of wear on them compaired to the others. I went with Champion double platinum plugs in mine. At the same time I changed the wires to the shorty crate engine wires ( they say they'll give more HP and a better idle... I don't compleatly buy into that but they do clean up the engine and look cool). The earlier 5.7's had some differances than the newer ones. I think your calls for 5w30 ( my '05 uses the 5w20... it's non MDS, '06 was the first year), My '05 has 4 o2's, that made putting true dual exhaust on a breeze. I'm not sure if your '04 uses 4 or 3 o2's, you'll have to check.
 
The O2's will trip the MIL when they go bad, but when they get lazy is when the alfa readings go to hell and the mileage suffers, and the light might not trip. The only way to know for SURE if the front O2's are OK is with a scan tool and graph the sweep. The image *should* look like a skier going through the Slaloms. If it looks like a fish slowly wiggling it's tail they need to be replaced. How the rear O2's respond will tell how the Cat's are working. VERY slow sweeps are what your looking for. If they cycle (like a properly operating front...) the Catalyst is suspect. Cleaning the throttle body is another good suggestion. Just make sure it's O2 sensor safe.

Don't forget it's winter time in our area. They always treat the fuel and my mileage always sucks this time of year.....
 
Yep. Was not available in the trucks till '06, and only in 1500's. This also EXCLUDES Megacabs. They don't have MDS either
 
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