Causes of Very High Fuel Consumption?

[soundman98]

Originally Posted by Tcoat

You were not around yet but there was a whole thread by a guy that drove two miles to work and then sat with his car running for 45 minutes at lunch every day. He would reset the average on the gauge every day so the bulk of the time it was pulling data was at idle. He could never quite grasp why his mileage was so horrible.

there was a story a long time ago that i read somewhere.

a co-worker bought a new chevy colorado, and was bragging at work about how spectacular the gas mileage was compared to his old truck.

so the story-teller said for the next 4 weeks, he would add 2 gallons every day in the parking lot to the colorado.

one day he stopped. and from that day forward, the co-worker started visiting the dealer every week to have them look at why the gas mileage tanked so bad!

[andrew4554]

check you alternator bearing. a bad one can cause lack of mpg

[Halo_2]

I would change the spark plugs and air filter.
Then recheck.

[chondo]

I’ve consistently gotten 2-3mpg lower than the digital readout indicates on stock 2018 brz. Could it be that it doesn’t read throttle blips when downshifting? Readout is 23mpg and I get about 21 driving 90%+ city and rev match most downshifts

[why?]

Originally Posted by chondo

I’ve consistently gotten 2-3mpg lower than the digital readout indicates on stock 2018 brz. Could it be that it doesn’t read throttle blips when downshifting? Readout is 23mpg and I get about 21 driving 90%+ city and rev match most downshifts

no all gauges like that are off a little bit.

[extrashaky]

Originally Posted by chondo

I’ve consistently gotten 2-3mpg lower than the digital readout indicates on stock 2018 brz. Could it be that it doesn’t read throttle blips when downshifting? Readout is 23mpg and I get about 21 driving 90%+ city and rev match most downshifts

I don't think any manufacturer has an accurate onboard fuel economy calculator. The system estimates your fuel economy based on fuel flow and is not very precise. A small error in one of the inputs becomes a large error at the readout.

Just keep doing the math and ignore the thing in the dash. I haven't looked at mine in years.