Big drop in gas mileage

[SHOPKINS]

Hello, I am new to the forum. My 2014 hybird has been getting a reliable 40 mpg for since i bought in used in 2014. In the last month or so the miles have dropped of to 30 or so. When I would refill before, I knew I had almost 500 miles to a tank. Now it is under 400, more like 375.

 

I swear I am driving it the same way. Any ideas on why the big drop in performance? Thanks. I am ready to do to the dealer.

[Larry Twitchell]

Sure to be many reasons, but I’d first check tire pressures all around. If that’s ok, I’d check the throttle body and just clean it up while there. YouTube has many videos on how to do this.

Good luck.

[ptjones]

I would try a good fuel injector cleaner, how many miles on the car? Did you just replace the tires with another brand? Did you change gas brand? Just thinking of all the possibilities. :)

 

Paul

[ethermion]

Tires should not make much of a difference. I replaced the OEM LRR tires with Goodyear Eagle F1s - much better traction - and we have noticed no difference in mpg.

 

Low tire PSI, maybe. Cheap and easy to check, though the FFH does have TPS which should light up if low pressure. TPS was mandated by the govies for fuel efficiency... I know for certain, as the TPS sensors went out on my 13 per a message on the dash, and had to be replaced.

 

Fuel injector cleaner, why not. Doubt it though. Just a few bucks, so whatever.

 

A 25% drop in fuel efficiency is pretty dramatic. I would expect something like that to throw a CEL, and/or have serious drive ability issues. Maybe a clogged exhaust? Leaking fuel system - as in dumping gas on the road? Dunno.

 

Puzzled here too. A dealer visit might be the next step. A local tech also might have free ideas he/she can share if you offer a smile and a handshake.

Edited July 20, 2018 by ethermion

[ptjones]

Tires should not make much of a difference. I replaced the OEM LRR tires with Goodyear Eagle F1s - much better traction - and we have noticed no difference in mpg.

 

Low tire PSI, maybe. Cheap and easy to check, though the FFH does have TPS which should light up if low pressure. TPS was mandated by the govies for fuel efficiency... I know for certain, as the TPS sensors went out on my 13 per a message on the dash, and had to be replaced.

 

Fuel injector cleaner, why not. Doubt it though. Just a few bucks, so whatever.

 

A 25% drop in fuel efficiency is pretty dramatic. I would expect something like that to throw a CEL, and/or have serious drive ability issues. Maybe a clogged exhaust? Leaking fuel system - as in dumping gas on the road? Dunno.

 

Puzzled here too. A dealer visit might be the next step. A local tech also might have free ideas he/she can share if you offer a smile and a handshake.

It's the tires, I would say you lost 3 to 4 MPG with the Goodyears and if you put the Michelin's back on you would get your mileage back. :) Here is a test by Tire Rack on the difference between LRR tires on Prius which was 3.8 mpg. https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=121 Performance tires are worse when it comes to mpg's. I put Goodyear Fuel Max tires on a 2007 Focus which had Pirelli P6 tires and gained 4-5 mpg as an example. :)

 

Paul

 

Paul

[mmarreco]

Tires should not make much of a difference. I replaced the OEM LRR tires with Goodyear Eagle F1s - much better traction - and we have noticed no difference in mpg.

 

 

I lost 5MPGs going from Michelins to Continentals PureContact low resistance. Can't wait to wear them out to go back to Michelin.

[md13ffhguy]

 

I lost 5MPGs going from Michelins to Continentals PureContact low resistance. Can't wait to wear them out to go back to Michelin.

Same...

[Cobra348]

Tires should not make much of a difference. I replaced the OEM LRR tires with Goodyear Eagle F1s - much better traction - and we have noticed no difference in mpg.

 

Low tire PSI, maybe. Cheap and easy to check, though the FFH does have TPS which should light up if low pressure. TPS was mandated by the govies for fuel efficiency... I know for certain, as the TPS sensors went out on my 13 per a message on the dash, and had to be replaced.

 

Fuel injector cleaner, why not. Doubt it though. Just a few bucks, so whatever.

 

A 25% drop in fuel efficiency is pretty dramatic. I would expect something like that to throw a CEL, and/or have serious drive ability issues. Maybe a clogged exhaust? Leaking fuel system - as in dumping gas on the road? Dunno.

 

Puzzled here too. A dealer visit might be the next step. A local tech also might have free ideas he/she can share if you offer a smile and a handshake.

You should check the cold pressure approxiately monthly. The TPS is not going to warn you until about 3-4 PSI low. For about $25-$30 you can get a compressor by Slime that uses the 12V outlet and allows you to set a shutoff point. It's worth the money and is available at AutoZone and other places.

 

The tires probably added to loss. Unless it's a LRR similar to the OEM stuff, odds are you will experience some MPG loss. My brother did that and dropped 2 MPG on his '13 FFH. He switched back to LRR tires after that and had great mileage. Only time I use anything other than LRR tread is Winter when I know my MPG is screwed any way due to conditions.

[ethermion]

Still not seeing how the OP would be getting around 30 mpg due to tires.

 

Checking tire pressure is always smart. Not only for mpg, but also for safety, performance and tire life.

 

As for my tires, nobody has to do what I did. Our car is a commuter car that does a 40 mile round trip each day in about 2 1/2 to 3 hours. I doubt tires influence mpg if you are stopped at a light, or doing 5 mph in traffic. We are happy. MPG is of no interest if you can't get up a snowy hill on the way home, or the car gets squirrelly in the rain. Our experience does not apply to other use cases.

 

Hopefully the OP gets this figured out and shares with the rest of us.

[Waldo]

Still not seeing how the OP would be getting around 30 mpg due to tires.

 

Checking tire pressure is always smart. Not only for mpg, but also for safety, performance and tire life.

 

As for my tires, nobody has to do what I did. Our car is a commuter car that does a 40 mile round trip each day in about 2 1/2 to 3 hours. I doubt tires influence mpg if you are stopped at a light, or doing 5 mph in traffic. We are happy. MPG is of no interest if you can't get up a snowy hill on the way home, or the car gets squirrelly in the rain. Our experience does not apply to other use cases.

 

Hopefully the OP gets this figured out and shares with the rest of us.

 

Well the m in mpg stands for "miles". So no matter what your result is, you have to travel some miles to have mpg. When you travel those miles, the tires must turn, therefore they will make a difference. Rolling resistance isn't like wind resistance, it's not really influenced by speed, at least not to the same exponential degree that wind resistance is.

[ethermion]

 

Well the m in mpg stands for "miles". So no matter what your result is, you have to travel some miles to have mpg. When you travel those miles, the tires must turn, therefore they will make a difference. Rolling resistance isn't like wind resistance, it's not really influenced by speed, at least not to the same exponential degree that wind resistance is.

Uh, sure. I get the miles part. I just doubt that LRR tires make a difference at stop light. Or facing a snowy hill, just a few feet of traction is the difference between getting home or calling ME.

 

Not offering that what works for us, will work for you. Just offering that tires will not drop a FFH to 30 mpg. Pretty sure about that. Bet money sure about that.

 

Still not sure we are helping the OP.

[ptjones]

At this point you have to wonder if this was real or not.

 

Paul

[lolder]

This is the only post of the OP.