04.5 Mileage dropping AGAIN months after reflash

[JCotte]

:{ Has anyone else had mileage decline after a period of time after the reflash was done? I had the reflash done in November and went from 15 to 19. 5 MPG all through the winter and now over the last month i am back down to 15. 5. has anyone else had or heard of anything like this happening. Any clue as to what might be going on with it. It seems to be running fine. :--)

 

[RN1]

Mine was usually in the 12. 5 - 13. 3 range before the flash. After the flash, I was seeing 15-15. 5. Since Janurary, it has been dropping back down into the 13's. Same driving, same stations, no winter fuel in this area that I know of. Pretty discouraging considering the price of fuel. Truck performance seems the same, don't really think I have any signs of bad injectors. Dealer called Cummins, and they were told that is good mileage for my combination... . Robert

 

[JCotte]

Thanks RN1. I think it is hideous to go backwards in fuel mileage. i also think it is totally rediculous to drop 25%. this is unacceptable. I have not changed fuel stops either. Blended fuel should be winding down and improving my mileage. not losing it. I am just about disguested with this truck.

 

[KevinO]

I've noticed the same thing i always buy at the same station cause it is been a minimum of . 15 cents cheaper so i don't think i ben driving much different. The rough starts in the morning are starting to come back and it doesn't have to be below 30 anymore either.

 

[JCotte]

Kevin.

What was your mileage at before and after the flash? where is your mileage at now? What year truck? I am not having Rough starts at this point... . YET

 

[jwilliams3]

Funny, I have had no flashes ever.

Mileage went into the 15's now its back down into the 13's around town!

 

[JCotte]

Funny, I have had no flashes ever.

Mileage went into the 15's now its back down into the 13's around town!

J williams... did you ever consider it might be all the BOM's?

 

[jwilliams3]

But in stock settings (which I usuall run around town) it should do better.

 

[KevinO]

i was getting 15's then the reflash and it went to 18's and now it's going back down and the last couple tanks have been in the 16's truck has 22k on it so it should be broke in i haven't changed anything on it but am installing a FASS pump today.

 

[DDahl]

Perhaps the oil companies are dumping their excess winter blend in areas that don't need or want it.

 

[Bertram65]

19. 5, that is some good mileage for a 4X4 auto, I would not complain about 15. 5 either, that is about average for me, my all time high is 17. 6, that was a trip when I intentionally drive easy and slow.

 

[JCotte]

Bertram. this is my fourth CTD and this mileage is ridiculous. i have never run under 20 mpg when unloaded. To think that it is OK to lose 25% in mileage is wrong. when you spend an additional 5500 for an engine and then lose mileage is something wrong.

 

[JStraw]

Just when I was getting ready to take the truck in for the reflash you guys have to come up with this Guess I'm back on the fence.

 

[jwilliams3]

Fass wont help any on the mpg side of things.

 

[JCotte]

JStraw. Get it done. This is probably not related. I think the flash did it good. JWilliams has the same problem and he did not get the flash

 

[RN1]

I also have noticed the white smoke, rough running at start up. Not all the time, and sometimes even above 60 degree temps. I can also tell the grids are cycling at temps in the 60's. Not sure why, but didn't think this was normal. Most of the time things seem normal, so I'm not all that worried about it yet.



As a side note, I was at the dealer this weekend and heard to '05s start up. I almost forgot when my truck used to be that quiet.

 

[MHirst]

If I am not mistaken the only thing the reflash does is reset the overhead computer, It does nothing to change the trucks performance,, I use the trusty odomiter to moniter my milage, 16 to 18. 5 on highway empty and 10 to 13 towing a load.



05 quad cab 4X4 stock with auto trans.

 

[DJennings]

I think you are mistaken, but I can't back it up with fact on what exactly is changed when they do the flash. The flash changed the way my truck drove, made it a little more responsive and a little quieter/smoother, and the mileage improved (hand calc'd). It had no effect on the small poof of white smoke I get when I start the truck unplugged.

 

[RN1]

I have always hand calc'ed my mileage. The overhead is more accurate now than before, usually about . 5MPG low. I think the TSB was for poor mileage, white smoke upon start up, and overhead computer accuracy. It definitely changed the way my truck performed.

 

[JCotte]

The re-flash, depending on which one you got modified the injector pulses, pre and post which was for White smoke, pinging and fuel economy. This made the engine more responsive. It also had a portion the adjusted the accuracy of the overhead which used to fluctuate 2-3 gallons off.