cole929

The kn&n was a drop in

swiftnet

The K&N will allow a little better airflow, so MPG should not drop. A clogged cat will absolutely kill mpg. I'd get the cat checked out. I highly recommend finding the Mazda service center with the best rating. Have them check your cat.

RJayX-8

Nubbie here, Just bought an 04 and the mpg suck i was on the highway and was able to watch my gauge just slow drop i only went bout 20 miles and burnt damn near just ova a 1/4 tank

04Green

iTrader: (1)

Check the threads in my sig. I would start with the first $100 stuff. If you provide data on car, miles, maintenance, stuff like that, people can help. After the $100 stuff, you can worry about other stuff.

Welcome to the club.

flashgordon91

Rjayx-8, there's no way your 8 is running normal. Yes, they get bad gas mileage but no where near that bad. You should have your 8 looked at or try some of the tips a few of the guys like to offer.

Flash

RJayX-8

First im going to look in to the flash, I work at a dealer as a Hyundai tech and we have a mazda dealer...imma get one of our mazda techs to check it out wit me and do the reflash first...I also have a CAI coming so that should help lean it out a bit and while im installin the intake i'll clean the MAFS.thanks I knew something ain't right wit but i'll get it fixed thanx man.

RJayX-8

alright me and the mazda tech checked out my 8 and we found there is a intermit. misfire, so i'm just going to hit up rotaryfx and get plugs and wires from there the ignition coils are the same as factory so I get employee discount on parts and I'll just get those form work. Start with that first.

Zero11534

I am new to these threads so please don't shoot me for asking for help. I have owned 3 RX7 and NEVER gotten as poor MPG as I do on my 04 Rx8. I drive a mix between city and hwy and I don't hit the accelerator much, yet the best MPG I can seem to get all around is 15.6. Most of my drive to work is though the country long roads not many stops then I hit the beltway (opposite of traffic). I drive at about 65-70mph in 6th gear (speed limit is 65). I do run the motor to read line as told by other at least once a week. I also use 93 oct (only) and let my car warm up before driving.

I have recently changed my Spark plugs, Wires and Coils. I can not figure out why I am getting so poor MPG I was expecting 18-20, I only have 58,xxx miles on my car. Any help would be welcome. I have scheduled a "Stealership" appointment as I can not seem to figure out what is going on. I fill up at 11.9 gallons and I only get around 174-180 miles 14.9-15(MPG) the most I've gotten out of a tank is 220. Please help as I know this is far from normal. Someone else suggested my Cat is bad yet I don't notice any poor acceleration.

RJayX-8

when u take it to the dealer have them check for ecu/pcm updates i work at a hyundai dealer that has a mazda side and me and one of the mazda techs went through the same steps changing the coils, wires and plugs which did help out some but there was an update that had not been done, after we did the update my mpg went up

redrex04

Hi I'm going.g to delete my other thread as soon as possible but I bought an 04 rx8.. Auto. . It got terrible mpg and then engine died so I just got it back after waiting three months in the dealer ship expecting 18-20ish.. And here I'm getting 12-14 city and 14-15 highway.. And yes I'm doing my calculations correctly by filling it up then another pump or two driving till empty then calculating... Wires spark plugs and coils engine core was all replaced techs said it has n flash... And the cat is fine.. No glowing or rotten egg smell... Have tried every variance of driving style with no improvements.. I thought it maybe be fuel filter.. But they apparently have a long warranty.. Or injecters. .? Fuel injecters cleaner??? Anyway any help is greatly appreciated.. Car starts right up and runs absolutely great.. Just horrid mpg. ..

Wallets

iTrader: (1)

I have a question i get around 245 for 14 gallons on 93 oct its been that way since i bought the car i am assuming this is horribly low??? My question is if i take it in to mazda and it didnt have the flashes would they do them for free?

ShellDude

iTrader: (12)

245 is pretty good if you're doing city driving. highway mileage should be much closer to 300, if not a little over.

I get 200 per tankful going to and from work 20 miles each way, primarily back roads.

If you don't already have MSP16 then your 8 has been off the radar for the past 4 years. There's been nothing new since then.

Wallets

iTrader: (1)

I drive back country roads which are mostly straight line i stop twice i drive 35 miles back and fourth from work so that 245 miles per tank is mostly highway miles. This past weekend i took a road trip which was 280 miles away. I had to fill up when i arrived at my destination and when I arrived home when i filled up both times it was 15.78 gallons so 17.78 pure highway driving with cruise set at 80mph

Rye guy

Okay I have a 05 gt 6spd, with 100,000km, and 10000km on a "new" mazda warranty replaced engine. with the new motor i have replaced/serviced the following, plugs, wires, coils, air filter, oil, coolant, transmission fluid, diff fluid, tires etc.. With this engine I have averaged 28L/100km or 8.4mpg!! The "M" flash was supposedly done when the new engine was installed. Once on a long slow highway trip I got 408km/253miles to the tank, but only once. I drive about a 50/50 split city hwy, the only mods are intake,catless midpipe, and catback. anyone have any clue why my 8 is so thirsty?

lgilbert50

iTrader: (1)

18 to 21 mpg 2006 Shinka, Ebay exhaust on country roads. City 16 to 18 mpg. I drive quite aggressively

Shinka#253

My gas mileage actually got worse, I cant figure out what is causing it either.

flashgordon91

Just got new engine from Mazda. Warranty had 5 days left. I get about 320 miles driving highway through tn, and 200 driving it like I stole it. Just got a blue voodoo shift ****, just one more excuse to drive it.

Jere Sainio

i start to feel like Sak Noel now that even though i roll much,use engine break,have extra good tires and ultra lightweight rims, drive like grandma in 95% highway,EVEN DONT REV OVER 2300 i still have mileage of a 15l/100km. AND Boys, you cant imagine how expensive it is to drive here.....
So is there some sort of trick that how it is supposed to be driven?
like always 3000+revs or something?

RJayX-8

Nope rotaries are just not good on gas they burn alot of fuel and a lot of oil, just one of the down falls of it's marvelous designs. and something we all live with

zoomman

people on here are stating they are getting 220 miles to the tank... which is what i get when i run it as low as it can go...but when i first got my 8 i was getting over 300 closer to 350. Is anyone else experiencing that type of gas milage? i do mostly interstate driving now too.

Tamas

iTrader: (1)

Doing mostly interstate driving should definitely yield 300 miles or above per tank. If you get only 220 miles, then there is some problem with your car. Most common causes would be ignition issues or low compression.

PeteInLongBeach

I don't consider 25 miles per gallon/gas and 3000 miles per quart/oil to be "a lot".

But, I guess it all depends what you are accustomed to and what your expectations are...

Jere Sainio

what do you think? people usually take too calm these things about bad mileage. i drive 90% highway like a grandma and i still get mileage of 13mpg whisch is 18l/100km. its ridiculous since its almost three times more that mazda has promised to it.i also notice that the tenmperature doesnt rise to halfway of the tmperature meter. what do you think there is problem with the car since it sounds like it runs smoothly. is there some sort of update with mazda about it?

ShellDude

iTrader: (12)

90% highway miles should be netting you far better than 13mpg. Pure highway mileage nets me 26mpg, easily.... and that's at 80-90 mph.

Maybe you should drive faster?

PeteInLongBeach

Ensure your plugs, coils, air filters, MAF are all serviced or fresh. Have the catalytic converter checked for integrity / flow. Get a compression test.