Can any of you mechanincs tell me what would cause my mileage to drop all of a sudden out of the blue? I have an 04 2500HD 6.0 with 4:10 gears it's a 4x4 crew cab I normaly get around 9.9-10.2 pulling a trailer and got 9.2 pulling my camper last month and got 8.3 this weekend I got 14.2 on the highway last month with nothing behind it and got 9.9 this past week I checked it with pen and paper as well as what the computer said. It instantly dropped like over night I have 123,000 miles on the truck also have a K&N air filter in it that was just cleaned.

What can I do to bring it up I had a tuner on it but didn't notice much difference so got rid of it a while back.

Thanks for any help.

 

driving into the wind towing a camper can make all the difference.
humidity, outside air temp, wind speed, all makes a difference. sometimes i get 15 towing my car trailer, other times i get 10 going the same road if its hot out.

 

Yeah but this isn't the problem, I drive this truck every day pulling a tralier it has dropped like over night for some reason that I can't figure out. It has never got 15 mpg LOL I only wish.

 

1. never judge based on single instance, any mpg calculations are subject to 10% varience, which is about right for you.
2. if it persists, look inot this:
- never fuel early in the morning, many stations have gas trucks coming in then, stirr crap from the bottom
- did you change gas station? stick to NEW and quality stations
- check your air filter
- read for codes
- O2 sensors? they'll do it
- run can of seafoam through tankful
- check drivebelt/-s
- running with a/c? windows down?
- check tire pressure

 

Not a single instance it's been like this for about a week or more now. I'll try the seafoam but all the rest is the same nothing has been done different same gas stations same everything I pull the same trailer Daily with the exception of my camper, The filter was cleaned not long ago (K&N filter) The MPG changed a while after it was cleaned. I will have it checked for codes no lights have come on I thought if a sensor (02) was bad it would make the check engine light come on? always with the A/C on. Tire presures are good. Not sure what the seafoam will do to help bring back the MPG?????

 

Anyone have an idea of what is going on with my truck, any mechanics ??

 

check/replace fuel filter
clean MAF sensor

 

The fuel filter is in the tank how hard is it to replace?

Where would I find the MAF sensor?

Thanks!

 

Just a thought, but in many different regions of the US the fuel mixtures change based on the season. We recently started the summer season and I wonder if this may be a factor for you.

 

No it pretty much is the same here it's been 90-100 degrees here for several months now. I am pouring a can of seafoam in tomorrow and see what happens I don't see it doing much but worth the try.