rx8fanatic2085

Okay, like most people on these forums gas comsumption has been a problem. I've been taking my car in total of 2 times for it. First they thought it was my air filter. So I had that changed. They changed the coils that were bad on the car as well. Now the 2nd time i bring it in. They tell me that the reason my mpg is horrible is because of my sound system. The two subs i have in the back that combined with the box has the weight of like 30-40 pounds is causing the poor mpg. Too me this seems absolutely retarded however i could be wrong and thats why i was hoping someone on here could tell me either way. Thanks. I currently am getting 11-12 mpg. city/highway mix about 70/30

canaryrx8

iTrader: (3)

extra weight is not going to kill your mileage unless we're talking a couple hundred pounds or so (or at least more than 30-40 lbs). Sounds like a cop out to me, take them out and see what happens, I'm willing to bet your mileage will still be the same or close.

brillo

Thats BS.

I would check the following

1. Clean MAF
2. Clean Airfilter
3. Clean Throttle Body
4. Check Plugs
5. Check coils
6. Check Plug wires
7. Run a bottle of Redline fuel treatment through the car.

after all that, then I would check the wideband and narrowband sensors, my narrowband may have an issue, and I think my mileage is suffering for it. Its also the sensor located in the cat, which subjects it to alot of heat.

msenzo

My lift club member weighs around 110kg (you have to MULTIPLY by a factor to convert to pounds
I weigh 80kg
I have a sub, amp, I replaced the stock 25W rear speaker with 420W pioneers. I have the whole shebang.
and I still get more than 500km range.
Perhaps they should start looking at the problem with more seriousness. this type of diagnosis shows a lack of respect for your problem.

Go48

That's a good bit of city driving. If the city driving includes lots of stops and idling at traffic lights and traffic tieups, your low mileage is not too surprising. Think about it. When your car is sitting and idling it is burning fuel but not racking up any miles. Also, if you warm up the engine for more than a minute or so before starting off, that will reduce fuel mileage as well.

You might want to take the car on an open road trip, burn up a tankful of fuel and then compute the fuel mileage to get a more realistic reading on whether or not there is something wrong with the car or if it is your particular driving situation.

ken-x8

How much do you weigh? Under 200 pounds? I weigh 230, and get the customary 17 mpg around town, 22-23 mpg highway.

A couple of highway trips with a 280 pound friend riding shotgun still came out 22-23 mpg.

Ken

tuj

I get 13 mpg, but my driving includes a lot of idling. This is pretty normal.

rx8fanatic2085

well the thing is. I had my engine replaced due to the recall. With that engine it was a more sluggish however i got 18-19 mpg city and 20-21 highway. I noticed this difference on my first fill up with the new engine. I keep telling them that but they just shrug it off. I had the sound system with the old engine too.

brillo

if its that new there will be some break-in necessary

Brettus

iTrader: (2)

Excellent advice Brillo .

Brettus

iTrader: (2)

No - I do close to 100% city with lots of redline shifts & still get 14 or better .