Allpar Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
256 Posts
Discussion Starter #1
My 06 is the 3.3 SWB, and I am only getting 14 mpg in mixed mileage, more city than highway. I have recently changed the plugs, wires, and one coil, that has gotten me UP to 14 from about 12 mpg. Shouldn't I be getting more like 18?
 

·
Virginia Gentleman
Joined
·
14,675 Posts
I would think it could be more, but these vans are fairly heavy and city fuel mileage suffers accordingly. For comparison, we use to have a '00 T&C Ltd AWD 3.8L and in local driving (more city than hwy) it would only average 15-16. Get it on the highway and it would easily get 24-25 mpg and as high as 26.

Okay - I looked it up. The EPA rating is 17 city/19 combined/24 hwy so yes, 12-14 seems on the low side. Even if you don't have the CEL on I'd check for fault codes. Can be done at any Advance Auto or Autozone for free. Might check for a dragging brake as well.
 

·
Super Moderator
Joined
·
21,364 Posts
All fuel mileage and tire pressures suffer in colder weather. All tires must turn freely off the ground (rears more than front) and set them at 35 front/33 rear.
A rich condition caused by tired O2 sensors may eventually set a fault code, but it may take a long time or not at all.
A scan tool may show the Fuel Trim in precent deviation from normal. Positive (+) percentage values would indicate fuel being added because of a PCM determining the need for a real or imagined 'lean' condition. You may not notice a slightly rich condition at the tailpipe or while driving (it might even feel good and strong), but fuel economy will drop.
 

·
Super Moderator
Joined
·
21,364 Posts
It would be a good idea to verify that the fuel trim is at a high positive value (greater than +10%) before resetting the PCM. The PCM usually is not the reason for a rich trim, but does what the O2 sensors tell it what the mixture should be.
If you reset the PCM without fixing the underlying reason, the mixture will creep back to rich in a short period of running. If indeed this is the problem to begin with. Fuel trim is a learned adaptable value that is reset with a battery disconnect.
Are there any stored fault codes or pending fault codes? Doing more than half of your driving in the city in winter cold, your fuel economy will be disappointing. 18 mpg might be expected in the summer in mixed driving in a lightly loaded vehicle.
 
1 - 5 of 5 Posts
Top