autowiz

hey guys. I have had my uplander for 7 or 8 months now. it is an extended wheelbase passenger van without the rear entertainment and power sliding doors. it only has 47k on the odometer. for some reason, my minivan gets ~16-18 mpg on the highway, and under 13 on surface streets with the a/c on. there are no trouble codes or check engine light, and the van runs great. I am just woundering if this is right and correct or what type of mileage I should expect and if I should be hunting a problem. these are terrible numbers for a v-6.

Papa Bear

On the highway at 60 mph my '07 will get about 30 mpg according to the computer.

Do you have a brake dragging? I run 38 psi in my tires.

Chevrolet Customer Service

Hey autowiz,

Sorry to hear that you are not getting the desired gas mileage in your Uplander. Is this something you were planning on having your local dealership address? If this is something you would like us to help you get looked at please reach out via PM with your name, contact information, VIN, current mileage, and involved dealership. I've also attached a helpful website regarding fuel economy and driving tips. Fuel Economy

Sincerely,

Jonathan A.
Chevrolet Customer care

Papa Bear

Are your MPG numbers based on the computer readout or by calculations done by real-time miles driven/fuel used ?

AlexLok96

What kind of tires do you currently have on the van? I currently have winter tires(which i will change this long weekend) on mine and my fuel economy is pretty bad, averaging 15 mpg combined city and highway. Also check your air filter and oil, those usually affect fuel economy

autowiz

falken ziex 912. brand new. I keep then at 40psi. i'm an auto mechanic myself, so I guess I will try to hunt this problem down myself. the van is in great condition, I got it from CarMax. low miles. clean title. kinda pricey, lol. since I've had it I have kept mobil1 oil in it, changed the plugs and wires(on a rack from underneath and without any disassembly) and I used ac delco plugs and wires. and I put a new air filter in it, serviced the transmission and flushed the cooler(used dex6 fluid). but it has always been like this. the van is just thirsty. and yes, it is the reading on the trip computer. when I first got the van, it had a problem with the fuel guage where once it hit 1/4 tank, it would drop to empty. I have been pumping high test fuel into it and it seems to be reading below 1/4 tank, now and I reset mileage, and it just trends to the same. it doesn't stink like fuel, I can stand next to the van idling for long periods of time and not smell fuel or rich exhaust.

tech2

what are the fuel trim readings? Is it a flex fuel vehicle, if yes, what is the fuel alcohol content sensor reading? if its skewed the fuel trim will be rich both banks

autowiz

no flex fuel it is lz9 engine. not sure about fuel trims at the moment, but i have hptuners, and while i have never lisenced the van's vin or applied the software to it, i can still log data with the vcm scanner. so i will create a log of city and highway driving and see where trims are at different loads and rpm. splendid idea tech2. i will report back my findings

autowiz

this is the uplander in question. an otherwise wounderful vehicle inside and out.

Papa Bear

A 1/4 tank will show empty if you park on a hill, in fact the van may not start.

Has the mileage been bad on this unit since day 1 or have you been fixin' on it until it's broke?