Drop in MPG
01-18-2018, 03:04 PM
#1
JK Enthusiast
Thread Starter
Drop in MPG
my jeep recently went from avaerage MPG 15.7 to 12.2...wth. I have 4.88 and 35, only thing I changed recently was my oil. Changed over to Royal Purple Synthetic 5W-20 from Mobil One Synthetic 5W-20. Been running the RP for past 1200 miles and just noticed that I wasn't getting my normal 220 miles per fill up and checked my average MPG which was at 12.2. Going to change my oil back to Mobil One but was wondering if anyone had anything to input. I usually have to add a 1/2 to 1 quart every 1000 miles. 85K on manual 3.8 2008.
01-18-2018, 03:25 PM
#2
Super Moderator
I saw a drop with the snow but mine didn't tank by 3mpg. I've been averaging a similar 15.7mpg (by hand) in the past couple weeks. I'm not sure if it's the crazy wind we've had or what.
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hornetman (01-19-2018)
01-18-2018, 04:19 PM
#3
I added a stubby front bumper (no winch yet) and it got consistently cold here around the same time. I dropped from 19.5 to 15.8 according to the computer...I calculated it by hand and compared it for the first 20,000 miles, and it was within 0.2 every time. I hope once it warms but up I regain some of those MPGs, but it's a wrangler...I try to not think about MPG's
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hornetman (01-19-2018)
01-18-2018, 06:59 PM
#4
JK Junkie
Temperature is a killer. I track mpg for every fill up and have been doing it from new through 95,000 miles. Cold weather makes mpg drop significantly, more so than any other factor with normal driving. I have use a few different oils including RP over 95,000 miles. Never has the brand of oil changed my mpg results.
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hornetman (01-19-2018)
01-19-2018, 02:01 AM
#5
JK Enthusiast
Thread Starter
Thanks all, just couldn't imagine such a drop without thinking i had a severe mechanical issue developing. I little warming trend in the forecast so hopefully will see return to normal.
01-19-2018, 04:14 AM
#6
JK Junkie
Check it out. Here is my MPG vs month of the year. My location in central NJ. It's been such a cold January. I've seen some of the lowest MPG this month compared to the previous 6 yrs I've owned this jeep. I track MPG for every fill up.
Last edited by rob_engineer; 01-19-2018 at 04:24 AM. Reason: add chart
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resharp001 (01-19-2018)
01-19-2018, 06:09 AM
#7
JK Super Freak
With the colder temp tire pressures drop, I always have to add a few pounds for the winter, and let a few out for the summer. Other factors can't really be controlled for, but tire pressures make a huge difference in rolling resistance.
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01-19-2018, 07:36 AM
#8
JK Jedi
Lotta fuel economy commentary I take with a grain of salt, but I know your log of data over several years, so interesting to see how it generally fluctuates with temps. I wouldn't have thought a 2mpg range.......and it's also nice to see apples to apples data since the jeep has stayed in the same form for so long.
01-20-2018, 03:56 PM
#10
JK Enthusiast
Winter gas is a butane blend....has a noticeable effect on gas mileage compared to summer gas
Also a warm engine is a efficient engine. The longer time for the engine to get to operating temp will cause you mpg to take a hit also
Also a warm engine is a efficient engine. The longer time for the engine to get to operating temp will cause you mpg to take a hit also
Last edited by Jake7978; 01-20-2018 at 04:01 PM.