Very low mpg, help plz - 986 Forum - The Community for Porsche Boxster & Cayman Owners

jb92563 · 12-14-2015, 02:14 PM

For short 5 mile trips with a couple lights I think 16mpg is normal.

The first couple miles the engine is still warming up and throw in a couple lights and it just plain lukewarm city driving.

My drive in the morning is 15 miles, 6 miles with 16 lights city driving and 9 miles of highway at 70+mph.

I get 230 miles on 12 gallons(91octane) which is about 19mpg city/hwy.

My computer says about 16mpg in the city parts.

On pure Hwy cruising I have seen as high as 30mpg on the computer in 6th gear @75mph.

Tailwind · 12-03-2018, 05:39 AM

I "filled" my car for the first time and I stopped when it clicked off at 13 gal. Had 200mi on the trip readout, so 15.4 MPG This was mixed driving. Around town, I'm at or below speed limit, keeping the rev's around 2.4K. Next fill I will try to squeeze ~16 gallons in (I went onto reserve right after the dentist visit and drove about 25 miles).
I plan to clean my engine and do a TB/MAF clean. I have fresh plugs. I'm going to take the advice given here about shift points.

Gilles · 12-03-2018, 11:03 AM

Tailwind, out of curiosity, what is your tire pressure..?

Tailwind · 12-04-2018, 06:34 AM

Quote:

Originally Posted by Gilles

Tailwind, out of curiosity, what is your tire pressure..?

29/36, as stated on the pressure label. Good thing I checked the spare. Apparently previous owner didn't; it had 2lbs in it. I aired it up to 60.

Tailwind · 12-23-2018, 07:02 AM

Second tank, 17mpg from ~ 105mi city, ~50 fwy.
I need to check the air filter, and track the fuel trims.

rexcramer · 12-23-2018, 07:35 AM

I have driven 17573 miles in just over 3 years. I am at 20.66 Avg MPG. Keep your tires at proper pressures and stay up on the maintenance. I think you are in the ballpark. How spirited do you drive? I have had tanks that measured low at +/-16 and high at just over 23. Safe travels.

Tailwind · 12-26-2018, 05:08 AM

Second tank, 17mpg from ~ 105mi city, ~50 fwy.

I also had this question, and found this thread:

How many miles on a tank typically?

A lot of perspective from forum members.

Tailwind · 01-16-2019, 11:29 AM

Just getting on the freeway, the reserve light came on. After a 35 mile round trip, the needle was half way between Empty and Positively. 14 gal fill with 276 on the Odo = 19.8MPG mixed driving, more freeway this tank.