Gas mileage

Tiny
CHELSEAHIGAONNA
  • MEMBER
  • 2007 CHRYSLER PACIFICA
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 1,800,000 MILES
I was wondering what could make my gas mileage go down. When I fill my tank now I only get about 200 miles til empty but I used to get almost 400. Does this mean I need a tune up? It also shifts hard out of first gear.
Friday, December 14th, 2018 AT 5:49 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,709 POSTS
Hi and thanks for using 2CarPros.com.

A tune up can definitely help with fuel mileage. However, you mileage has nearly dropped in half. The first thing I would check is to make sure the air filter is clean and nothing is blocking the air intake/induction tube between the filter housing and the throttle body.

Here is a link that shows in general how a tune up is done:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

Here are the directions specific to your vehicle for the air filter. It shows how to replace one. Check yours first and make sure it isn't plugged. If it is, replace it. Also, make sure the air induction tube is not blocked by anything. The attached picture correlates with these directions.

1. Install the air filter element into air box.
2. Move cover so that the tabs insert into the air box.
3. Seat cover onto element housing and tighten the screws.
4. Reconnect the air inlet tube and tighten clamp.
5. Connect the intake air temperature sensor wire harness connector.

One last thing. If the check engine light stays on when the engine is running, you need to have the computer scanned for diagnostic trouble codes. Here is a quick video of it being done:

https://youtu.be/YV3TRZwer8k

I realize most people don't own a scanner. If you don't, most parts stores will scan it for free. Only do this if the check engine light stays on while the engine runs and doesn't turn off. That indicates there are diagnostic trouble codes stored.

Check these things first. Also, let me know how long it has been since the last tune up and the correct mileage.

Take care,
Joe
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Friday, December 14th, 2018 AT 7:47 PM

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