Guys, I am hoping you can offer some assistance here.

I recently moved from TX to TN and put new tires on right before making the trip. (I went from 325x65x18 to 295x70x18 Terra Grapplers) I drove the 900 odd miles with the new tires pulling a 7,000lb bumper pull trailer and had great mileage, around 11.5 mpg on the trip. I usually get around 11.5 - 12.5 mpg unloaded on the freeway and 10-11 mpg around town. (I have hand calculated mpg every full up and kept a log)

After I arrived in TN, I then had the truck serviced, its 45-50K first service at dead on 50,000 miles. I run Mike's 87 performance/tow tune and I forgot to put the standard tunes back on before taking the truck in. I also have a 2" leveling kit on the truck which shifts the front axle about 1 inch to the left. At this service I had the Ford dealer replace the front track bar with an adjustable one to put the wheels back to center and an alignment done.

After this service, my truck is doing around 8-8.6mpg in town and does not go above 9.6mpg on the freeway. I then put the truck back to the standard tune and took it back to the dealer mentioning the bad fuel consumption after the service and they said they could not find anything wrong. I reinstalled the 87 performance/tow tune and still getting the same results, this is still after about 4 full ups now trying different brands with no luck.

I have never had such bad fuel consumption and regretting the service as the truck was running so well before.

Do you think the them dropping the front axle to install the trackbar could be causing something to bind upfront, do you think there could be a difference in fuel blend in TN, something caused by not removing the tune before the service or just something else going on?

This huge drop in fuel is really disappointing especially since I was thinking the slightly narrower tires were going to help fuel consumption.

Thanks all

 

A common cause of high fuel consumption after a service is overfilling. The fluid level in everything that was serviced needs to be checked.

It is possible that there is now something wrong with the front end alignment. If so it should show up on tire wear by now. Run your hand across the front tire tread in several directions. Does either tire have raised edges or uneven surfaces? If so, the alignment is wrong. Sometimes it can be wrong without showing up like this. Did they give you a print out from the alignment to show where everything is set?

 

Actually, I forgot to mention, this was an aftermarket replacement adjustable track bar that they said they would install for me.

I did notice a vibration that started at 60mph and went and had the tires rebalanced. This did not entirely solve the problem and there is still a noticeable vibration. Since I have not being doing much freeway driving, I forgot about that issue.

When I looked up the instructions on installing the track bar it did seem the whole front axle had to be disconnected and lowered. When I took it back after the service I took the instructions in and asked them to make sure they had done everything right. When I picked it up they said they did not find anything wrong on the track bar either.

I think I am going to go to another Ford dealer and have them check it over and re-check the alignment. Also, they did not give me a print out on the alignment.

Thanks for the response. Hopefully you guys will give me a lot of good questions to ask when I take it in this week for a second opinion.

 

Remember anything that affects rolling resistance affects fuel mileage, small things like more aggressiveness tires, alignment out a little or even your brakes dragging a little will make a MPG difference.

Denny

 

Could also be fuel blend and terain. Flat in Texas? to hills in Tennessee?

 

i would say fuel blend is a high possibility and winter fuel.

 

I too am leaning toward the different fuel blends affecting you MPG. Also my plugs were shot at 50k miles, so you might want to change them.