Loss of power and loss of fuel mileage

[hoogkar]

Loss of power and severe drop in fuel mileage



--------------------------------------------------------------------------------:Sorry! reading all the previous posts I posted this in wrong Forum!!!



I am experiencing a loss of power and my fuel mileage has dropped drasticall. Just came back from the dealer and he said he is ordering a fuel pump - does this make sense?



I normally run about 20. 5 mpg om the highway at about 70 mph and for the last two weeks it has been down to about 12. 3 at same speed and conditions.



I have good boost (22 psi) and fuel pressure has been running about 8 at idle and will drop to 4 at WOT. .



with the price of fuel this is killing me -- any ideas?



I read about an IAT causing poor mileage - where is this located?:

 

[mattymac]

IAT is the sensor by the air box, Have you checked your oil? Could be injector related. I have also seen CP3's have the same symptoms from low rail pressure.

 

[JDerrick]

the fuel mileage has been trerrible in my 06' started out at about 17 when I picked it up fromt he dealer, that lasted for a little while, then started going down hill. When I was in Pahrump for MM 07', the truckwas only getting 11. with or withour the 8000 pound travel trailer, 11 mpg!!! called my old mechanic friend at a dodge dealership in Vegas, he reflashed to computer and told me about the fuel mileage going up a bit when the truck hit 10,000 miles. It did do this, that lasted for now now, but im still not seeing the 18-20+ miles per gallon that everyone is touting with these trucks. my 99' with 140K on it regularly turned between 18 and 23 ( depending on how hard i mashed the accelerator.



So now I guess there are 2 of us with fuel economy questions ... .....



Jim

 

[Lifted Mega]

That makes 3 of us. Still the dealer tells me that it will increase,i'm now at 16000 miles and im just like you as for mileage. I wish there was a dealer that showed some concern:-{}. They only are concerned if your rig is not running.

 

[BHolm]

You guys are just too impatient:-laf When delivered my '06 Mega was getting mid 13's. By 46k miles it was getting 20. I doubt you will ever see that though with a lift and 35s.



This is truely a medium duty truck engine. The vast majority of us do not run the engine nearly as hard as it needs, to break in quickly. It can take 30k miles, even if you think you tow fairly often.



I have pulled some heavy loads with all of mine, the harder you work them the better. I am talking about ten to fifteen hour days with the boost gauge over 20 psi, and some of those days right into the wind, making 30 psi of boost for hours. I honestly believe that is what it takes. I have seen milage increases take place after one of my heavily loaded 3500 mile round trips.



The guys with the 6. 7s are singing a similar tune. 14-15 mpg, but those trucks are all far from broken in. The best I ever had was the '03 QC SB 4x4, 3. 73 auto with the 305/555 engine. That was used as a work truck, always pulling a big gooseneck. I used it personally for a while when it had about 75k miles. I was getting an honest 23. 5 mpg with it doing the same drive my Mega would get 20 on. My current truck with the G56 gets around 18. The autos are geared slightly taller in OD.

 

[CDonaldson]

I'm only at 16K on the ticker and I can say that at 10K I saw a little increase, then at 15K I saw a little more. I changed the intake early on, so the 10K and 15 K increases were with no changes anywhere. I recently changed to a ME kit and new GDP intake horn, also changed out the diffs to Amsoil Severe Gear 75w140. It was 75w90 Mopar that was done at 5K, cooked the paint off the cover, so I upped the antee to the Amsoil and added a MagHytek cover. I instantly got 2mpg the last 1K miles with my most recent changes. I also think that since the HOT weather in my area my engine is getting up to better operating temps, plus I have been towing more. Most all my driving is a max of 3 hours going somewhere, so maybe longer running times will also make a difference. I'm getting ready to do a 4K trip, towing my 5er, I bet that will also make a difference. Hang in there, they will get better from all I have seen when you start putting on some mileage. I have a friend who started breaking 20mpg with his 4. 5 6-speed 4x4 at 75K.



CD

 

[smokejunkie]

Loss of power and severe drop in fuel mileage



--------------------------------------------------------------------------------:Sorry! reading all the previous posts I posted this in wrong Forum!!!



I am experiencing a loss of power and my fuel mileage has dropped drasticall. Just came back from the dealer and he said he is ordering a fuel pump - does this make sense?

this makes sense to me. I had my mileage drop dramatically about a month or two ago and took it to the dealer and everything was in spec. Then last friday my lift pump went out. I just got her fixed last night so I don't know for sure thats the culprit for the drop in mileage but the way everything happened on my truck it really makes sense.

 

[JDerrick]

HHHHHHHHHHMMMMMMMMMMMMMMM So I suppose that patience really is a virtue when it comes to fuel economy with these new trucks. I believe BHolm hit the nail on the head with his statement "This is truely a medium duty truck engine. " I'm just not feeling very virtuous with the fuel prices being what they are. . On a happier note. The Walker muffler P/N 21171( purchased from NAPA) has been a great improvement to the truck. Not very noisy untill you reach higher boost levels. Im sure it will help reduces the EGT's next time I take the travel trailer out for a drive. I also moved the discharge of the whole exhause system to just infront of the right tire.



cheers ... ...