You missed 1 important step, you need to fill the tank up again so you know how much fuel was used for that interval, it will never be the full capacity of the tank because you will never drain it dry.

Yes. Also consider that the extra ethanol additives they put in winter gas negatively impacts fuel milage as does the typical longer warmup times that engines experience when starting temps are low.. and that can be compounded if you let the vehicle warm up excessively(more than a minute) before driving away.

 

 

ok. I am going to hold on this over the next week so I can get you exact answers. Of course, with gas prices the way they are, I can't even get a full tank on the 75.00 limit at my local gas station

 

I live in South Florida, so starting temps are rarely ever particularly low

 

 

Replace the O2 sensors they and the MAF sensor are the main contributor to fuel usage. There are also other sensors that are used but those are the main ones that are used to calculate fuel trim. Get a hand held scanner and see where the o2 sensors are running.

 

If you want an accurate gas mileage check from a single tank of gas:

Fill it up. Let it click itself off and don't try to add any more. (The limit isn't $75 because you can't buy anymore, it's their pre-approval amount, Just swipe your card again and keep going if you have to)
Either reset the trip odometer or write down the mileage (I always write the current mileage on my receipt)
Drive some, it doesn't have to be the whole tank.
Go back to the same pump at the same station at about the same time of day and fill it again, then do the math. (I use Fuelly.com)

This is how they do the official EPA mileage checks.

 

Miles and year should not be a problem. I bought a 2010 E350 V8, 5.4 (very likely as yours) with 210,000 miles and dumped a lot of money turning it 4x4.
My mileage is 11mpg after the 4x4 and I drive with zero regard for mileage. Your should be 12or higher.
Keep the van, it suits your needs and trading for something else do not warrant any improvement. CHANGE MECHANIC. I do all my work, but $400 for plugs seems excessive and he also seem clueless on what your vehicle need.
Mileage is not great, but these vans are easy and cheap to maintain. Keep it.
Before you change the MAF sensor, try replacing the air filter and while doing it, you will see the MAF and clean it.
Brake dragging or wheel bearing failure could be an issue. After a long drive, place you hand on the middle of the rims and try to feel is one is hotter than the rest. Also, while coasting, roll your window down and listen for some dragging noises. Have one of your kids do the same on the passenger side.

Good luck.

 

A little trick I do when listening for noises sometimes is to roll the windows down and drive beside a building or long wall. 3 or 4 feet away and you can hear sounds you never knew you had. If your back or side windows pop out that will help too. Do it on both sides.

 

I drive an E350 PSD and have gradually replaced many of the aforementioned items.

I replaced tires, ball joints, shocks, radius arm bushings, radiator, brakes, rotors, AC condensor, instrument cluster, batteries, valve covers,...the list goes on.

May seem expensive, but considering how heavy and heavy duty these beast are, these are normal expenses performed every 100k. Now the repairs seem cheap because I will not have to replace these items for a long time. My van has 808,000 miles on it and it drives nice and tight. Diesel fuel is the cheapest expense for this beast. Fuel economy is not much better than the 5.4 or V10. I average 16.5.

When my radiator cracked, I replaced it with an aluminum radiator.

Keep the van. Everything is replaceable. I don't think my van having so many miles is an anomaly. It's an industrial piece of equipment meant to last.

 

Ok. I still have not gotten to the next fill up yet. Does anyone have a mechanic to recommend that is reliable and not terribly expensive here in South Florida? After bringing the van in for clicking on the steering wheel and spending an awful lot on repairs I drove out and noticed a bit later that my steering wheel was still clicking. The mechanic felt really bad about it and told me to bring it back when i can. Really frustrated


Thank you

 

Where in South Florida?

 

I live in North Miami Beach

 

O2 sensors will kill your mileage. Even if they are not quite bad enough to throw a code. Replacing those, cleaning your MAF and checking for any stuck calipers would be where I would start.

 

The clicking sound in my steering wheel was a center link tie rod.