Jeep Garage  - Jeep Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
My 13 5.7l is currently getting about 10mpg, compared to the 16-17 I got when I first bought it. I’m new to engines and such, what are some things I can change/clean to help increase the mpg
 

·
Registered
Joined
·
8 Posts
My 13 5.7l is currently getting about 10mpg, compared to the 16-17 I got when I first bought it. I’m new to engines and such, what are some things I can change/clean to help increase the mpg
How many miles are on the vehicle? Have you checked the engines air filter?
 

·
Registered
Grand Cherokee
Joined
·
3,132 Posts
As well as the Air Filter (a big one, if your's is clogged, and if its never been changed, just go out and buy one and replace it)...

Open your O.M. or download an .pdf copy if you don't have one, review the maintenance schedule and catch the vehicle up on the overdue maintenance....

Spark Plugs worn out will drop mileage also, the change interval for the pre-'14 Hemi is 32k miles. Yes, lots of people report going well over that and not suffer the symptoms of worn out plugs, like poor fuel mileage.... ....when I changed my plugs at the recommended 32k mi interval, they looked like they only had a 1k mi on them, the gap was exactly the same as new.... ....but if you haven't changed the spark plugs yet, well you're approaching 3 times over the recommended change, that could reduce your mileage, power and make the engine rougher running....

Do you have a check engine light? They put that there for a reason, even if you don't, check for stored trouble codes and try to correct them.....

Partially clogged fuel injectors can reduce mileage, fuel injector cleaner added to the gas tank can't hurt.... ....a lot or barely effective, the most popular, because they are seen as the most effective is Chevron Techron or Lucas Fuel Injector Cleaner..... ...if you've never used it and at your mileage, I would buy enough bottles for 3 tank fulls in a row, keep them in the vehicle and add them for next three tank fulls.... ...you don't want to soften and only remove half the deposits just for them to harden even worse, run several tank fulls to make sure you blow it all out....

Clean your PCV valve, if its dirty or gummed up it will let too much air pass and that will be like a vacuum leak that can drop mileage..... ...the Fed makes manufacturer's warranty emission equipment to 80k miles, so if they recommend checking/cleaning/replacing the PCV valve that means they would have to do it for you for free under warranty..... ....so notice they all put check/clean/replace the PCV valve right at 80k miles when the warranty is up.... ....check and clean it sooner than that......

Check you have the right dipstick, many Hemi's came with a mis-marked dipstick, causing you to overfill on oil if you fill it to the fill mark.... ...overfilling on oil can cause you to burn oil and burning oil could lower your mileage....
 

·
Registered
Summit
Joined
·
55 Posts
Some of the loss can be contributed to winter gas blends. My Hemi dropped from 19 to 17 mpg. and others seem to see the same or worst.
 
1 - 7 of 7 Posts
Top