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Poor gas mileage on 2000 Dodge Caravan

Hi, I have a 2000 Dodge Caravan with 104k miles. This winter, I’ve noticed the gas mileage progessively declining. I was averaging 12-13 mpg around town. I took it to my local mechanic who is a former Dodge mechanic. He looked under the hood and noticed that the hose running from the PCV valve to the EGR sensor was disconnected and causing the gas mileage to decrease b/c too much air was being sucked in. I replaced the hose and PCV valve but this didn’t help the mileage. The mpg stayed the same according to the overhead dash. I then reset the computer but disconnecting the battery cables for 15 min and the touching the + and - together before reattaching them to the battery. This didn’t help the computer relearn that there wasn’t a formerly a major air leak. The mpg remained at 12-13mpg.

I took it back to my mechanic who then ran the OBD test and found the van to be in top shape. No red flags reported. It was running great he said. He was puzzled about why the mileage was so low. I even manually checked the mileage which was still at 13.6 mpg. The overhead dash was reading 12.8 mpg.



Any help on why the mpg is so would be greatly appreciated. The car used to get 16-17 mpg around town.



Thanks

Andrew

Were there any error codes recoded by the OBD?

When was the last time:

  • oil was changed w/ filter
  • air filter changed
  • fuel filter changed
  • plugs and wires changed

Are all other maintenance items listed in the owner’s manual up to date?

Note: winter time usually results in lower mileage due to cold temperatures and winter fuel which has less energy.

Other than the items listed by JEM - check the tire pressure regularly. You might also ask whether the mechanic has checked the cooling system - in particular the thermostat and the coolant temp sensor. If the coolant runs too cool, or the sensor says it is too cool, then engine runs rich. This should be checked even if there are no signs of problems w/ the cooling system.

You might also keep in mind that wintertime around town driving will result in the lowest mpgs you will ever get.

Hi Joseph,
There were no error codes on the OBD. My mechanic said everything was running great. I talked to him again today (2/27) and he’s at a loss.
The oil and filter are changed every 3000 miles.
Air filter was changed 1 month ago.
The fuel filter was probably changed 3 yrs ago.
Plugs and wires were changed a year and a half ago.
I keep the tire pressure at 35 psi.
Most of my driving to and from work is semi-city driving just outside of Boston.
Mon-Fri I rarely drive over 40mph.

Yes, I realize that winters are the roughest on car performance. The mpg just seemed lower than previous years.

Thanks for your reply.
Andrew

Hi Cigroller,
I haven’t thought about the thermostat and coolant temp sensor. My mechanic didn’t mention it either. He’s a former Dodge dealership mechanic who runs his own shop now. He also drives a Caravan. I’ll run that by him and see what he thinks. Thanks for your suggestion. Hopefully that’s the culprit.

Thanks
Andrew