VERY poor gas mileage thread:
 

OK...I've had my FD for quite some time now. Ever since I've had it, I've been averaging extremely poor gas mileage of 7.3 MPG.My car isn't super-highly modified and I've changed everything that I thought could affect mileage, including:

Fuel Pump,
Fuel Filter
Spark Plugs,
Plug wires,
Adam C intake,
Downpipe,
midpipe,
RB dual tips,
O2 Sensor,
powerFC

What else do you recommend me to do in order to remedy this? It's staring to bug me that I need to refill my weekend driver EVERY weekend!

Any tips would be much appreciated.

Thanks,

Ian

You should try getting it tuned. You might be running rich.

+1

like holy shit rich... 7.3 mpg on those mods is insanity...

Did you buy the powerfc new, or from someone on the forum? Something defiantly isn't right.

Lead foot? Over-rich tune? Slipping clutch?

ya tuning for sure but you do own a rotary so bad gas mileage is expected just not that bad. i had the same problem until it was tuned now i get better mileage than my truck!

All city driving, with a heavy foot can easily lead to single digit mpg's. I was getting about 9 mpg before the recent rebuild. I will be interested to see what it does now.

Drop that POS off at the nearest Chevy dealer & trade it in on a new Vette.

Performance & the gas mileage you desire.

Problem solved....................

lol

the C6 is a great car, but I would still miss the FD....I'm looking at a C6 as a dd, though

anything less than 14 mpg is insane, even with an FD (for the street)

You might also want to add to your list to check for a gas leak.

I'd cry with tears of joy if my FD got 14mpg.

heh, you and me both.

I consistently get 14 city and 20 on the highway, and I drive aggressively...the run runs 15-16 AFR at cruise and 10s at idle lol

I was recommended by a mechanic to check these:

1.Check for good ignition on all 4 plugs
2. Bad Coil?
3. Check for bad ground for O2 sensor on Ground Loop using digital voltmeter (0 - 5 volts)
4. Check fuel pressure

Do you think these are worthwhile to check out?

I drove from Atlanta to Miami and averaged 86MPH including one gas stop and some highway construction. I still got 22 MPG which I thought was pretty good. Around town on the gas, I'm estimating that I am also in the single or low double digits.

On my way back, however, I shipped the FD and drove an 06 Civic and got 36 MPG with the A/C on!

I would say go with a tune of the pfc and check for fuel leaks.

Jeff

lol, just just driving around, few little mountain roads i spent 140$ in 2 days this weekend. in just gas.. whats the cheapest solution for quick fuel tune right now? afc? cant afford a powerfc for a while. any ideas?

I do not mean to hi jack this thread at all. You can try doing a tune up, do wires, plugs, fuel filter, o2 sensor, clean/replace intake filter, get hard pipes for the intake if you dont have them already, catback exhaust, downpipe, intercooler. The modifications should help deliver colder air into the motor which will help lean out the fuel mixture. I was getting 16-18mpg on the pettit unlimited ecu, with the PowerFC I noticed increased driveability and gas mileage being between 18-22. You can also try to get a HKS twin power to help burn the fuel better. Just make sure you dont have any kind of boost spikes or creep and don't go past 10psi for the stock ecu.

the best mod I have purchased was a good tune. i had my single setup tuned by gotham and it is the most well-spent $$ on my FD in the 8 or 9 years ive had it. this will greatly improve your low mpg or at least give you a good idea of what is causing it

like they said before ^, drive a 6 speed vette. my C5 gets 27 on the hwy and 21 city with 335 dependable rwhp.

that would just be the gas fumes in your eye