Sudden reduction in MPG - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 06-26-2015, 05:43 PM   #1
Registered Member
 
Join Date: Jun 2015
Posts: 2
Country: United States
Sudden reduction in MPG

Hi, I'm new to the forum and have a fuel economy issue I really need help with.

Car in question is a 2002 Chevy Venture van, with 200,000 miles on the od. I have kept careful records in the 90,000 miles I have owned the car and it has averaged 21 to 22 mpg (combined city/highway) and 25 to 27 mpg highway.Better in winter than summer of course.

Recently (and rather suddenly), both in town and highway mileage has dropped about 3 mpg.There is no question about this as I have an ultra gage and a OEM in car mpg computer and both are backed up by manual calculations.

New plugs, new oxygen sensor, new air filter, new gas filter, same gas station, same air pressure in the tires (40 psi) ..... and nothing has made a bit of difference. It has been very warm here (mid 90's) but that happens every year (just a little later).

Can anybody tell me where to look next ?
__________________

schuh8 is offline   Reply With Quote
Old 06-26-2015, 08:40 PM   #2
Registered Member
 
Join Date: Nov 2007
Posts: 1,460
Country: United States
Location: north east PA
Where are you located? Could your stations have switched to E10 from straight gas?
__________________

trollbait is offline   Reply With Quote
Old 06-26-2015, 11:01 PM   #3
Registered Member
 
RobertV's Avatar
 
Join Date: Feb 2013
Posts: 1,900
Country: United States
Location: San Antonio, TX
Running your A/C?
RobertV is offline   Reply With Quote
Old 06-27-2015, 12:32 AM   #4
Registered Member
 
Join Date: Aug 2009
Posts: 2,483
Country: United Kingdom
Location: Mid Wales
I would say a small decrease like that is normal, if it had dropped by 10 MPG, I would be more concerned. There is a 7 Mpg difference between my best tank and worse, there are so many things that affect mpg, I doubt youre driving style alone would remain consistent enough to keep the same figure.
__________________

Please subscribe to my YouTube channel
Draigflag is offline   Reply With Quote
Old 06-27-2015, 05:13 AM   #5
Registered Member
 
Join Date: Jun 2015
Posts: 2
Country: United States
Thanks guys for all your replies.
I always use the same station and they only have E10. If they had switched to straight gas my mileage would have improved.
When I run the AC I get about 0.5 mpg drop. Nowhere near enough to account for my 3 mpg drop. If I compare summer mpg with previous summers I still get a 3 mpg drop.
At each fillup I record gallons, miles, the ultra guagempg estimate and the car computer mpg estimate and compare them all over time. I could probably notice a drop in mpg of as little as 0.5 mpg over time. A 3 mpg drop is huge! Almost 15%.
I'm convinced its related to failure of some engine component and yet I'm not throwing any codes.
I'll be driving from Florida to Colorado in a week and the loss of mpg works out to $80 more in gas.
schuh8 is offline   Reply With Quote
Old 06-27-2015, 08:24 AM   #6
Registered Member
 
Join Date: Nov 2007
Posts: 1,460
Country: United States
Location: north east PA
Have you checked your brakes?
Perhaps one or more are now dragging on the rotor.
trollbait is offline   Reply With Quote
Old 06-27-2015, 08:40 AM   #7
Registered Member
 
Join Date: Aug 2009
Posts: 2,483
Country: United Kingdom
Location: Mid Wales
Might be a silly comment, not sure how the weather systems work over there, but over here in the summer the wind changes direction bringing warmer air from the south. If the same happened there, you could be heading into a slight headwind without knowing, and missing a tailwind which in a boxy Van could make a difference.
__________________

Please subscribe to my YouTube channel
Draigflag is offline   Reply With Quote
Old 08-20-2015, 10:18 PM   #8
Registered Member
 
Join Date: Jan 2014
Posts: 104
Country: United States
Quote:
Originally Posted by Draigflag View Post
Might be a silly comment, not sure how the weather systems work over there, but over here in the summer the wind changes direction bringing warmer air from the south. If the same happened there, you could be heading into a slight headwind without knowing, and missing a tailwind which in a boxy Van could make a difference.
I second this suggestion.

Also, how many tankfuls have you been experciencing your 3mpg loss?
__________________

ChewChewTrain is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 01:14 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.