Today I went in for a dealer oil change, and complained about poor mileage (I stated I thought it was fouled plugs), mis-firing engine at idle, and squaky brakes too. They were very well educated about it and proceeded to check my PCM (had a pending mis-fire code), replaced my fouled plugs with the hotter variety, told me brakes will stop squeaking after more breaking in, and replaced the oil with Mazda issue 5w20.

They reflashed my computer with newer settings and reminded me to check my oil every other fill-up.. yada yada. I'll compare new plug/reflash mileage against what it had degraded to and post results in here on next fill up. When I purchased my 8 i was getting 18.5 in the city (September), it had fallen to 13.5 as of this week. The car now has better throttle response and idle than when I dropped it off.

Just wanted to contribute some information and post some before and after information after my reflash/plug replacement.

Very interesting side note: They just received a memo on a new Mazda accessory of sorts. It is called a Renesis Desk Toy, and is a model of the renesis encased in acrylic with RENESIS written on the base. I guess there is a crank on the back that you can turn and watch the rotors spin around like mad. It looked really cool.. about $80 i think.

 

That is good news let us know how it goes in the next week or so.

 

Cool- looking forward to seeing results of your re-flash.

BTW, this is probably the desk accessory you heard about- looks like a fun toy to play with when I'm pretending to pay attention on conference calls
http://www.finishlineperformance.com...&preadd=action

Hopefully the price will come down a bit...

 

Yep, that's the one! Damn, that is expensive.. I think the $80 I saw was dealer price.... :p

 

my brakes still squel like a PIG after 11500 miles

 

I love that rotary toy. Too much $ though.

 

i want the rotary toy too. and btw my brakes have never squealed from day one.

 

Mine do but only when it is down below 20* F.

 

My brakes have never squealed either, but I do have mis-firing, although my mileage is still fine. I assume that it's from fouled plugs as well. However, I am interested in the re-flash. I am wondering if the re-flash will lower our mileage, and not raise it, so please get back to us on that. Other than the mis-firing, I'm pretty happy with how my car is running, and I'm not sure that I want a reflash. Keep us posted. - Haze

 

I typically refill once every couple weeks, so it might be a while before I post first numbers... unless I drive all weekend. hmm.. that's not a bad idea.

My brakes have only really gotten squeaky since it has been cold too. Might be a combination of cold + nasty salt residue on the pads. What really sucks the most is the fact that they squeak AND leave dust everywhere.

I went and checked the work receipt slip just now and they actually stated the reflash was a fix for my faulty oil light (i haven't gotten new oil pan yet). No customer has even brought that matter up with them until today. I had taken in a printout of that TSB as ammo just in case. I wish I had a photographic memory so I could recall the exact code the PCM had stored for the mis-fire... they wrote it down on the "internal" paperwork.

One other funny thing that happened was when I was chatting with the service manager the tech came over and was confused by something regarding the supposed port campaign work done called "OIL GAUGE REPLACED". I think he was saying it looked like I had an old dipstick. I was standing over the managers shoulder the whole time and got to see all sorts of interesting things on their computer.. but I didn't care what the tech thought as long as I got new plugs and the reflash.

I also am giving the Service Manager (who also is the webmaster for the dealership) the URL for rx8club.com and lit the fire for them to give that info to all future 8 buyers. Now I just need to get them to do mazdaspeed work.

 

Did your misfire set the check Engine light, or was that code stored without the light coming on. All I've got is a really nasty back fire at idle ALL THE TIME, full gas tank or empty, hot after being run, not run, all except on cold starts, then it idles fine. It's driving me up the wall, and I really want the hotter plugs. It also started doing this before winter set in so it's been there a while. Does this sound like what you had?

 

My engine light never came on, they retrieved a pending code. That sounds exactly like what I had, take that sucker in and complain about the mis-fire. If it is the same problem they will find a code and will replace your plugs.

 

That is very cool to know! I have been wondering how to deal with proving that I have been having the problem, and that should do it. Thanks for the information. - Haze

 

I too have the same problem as Haze and Ranger. So, if I understand this, the best proceedure to insure that the dealer will change to hotter plugs and a reflash is to bring in the TSB and tell them about the misfire? The TSB for plugs do not reference a misfire. In fact it does not even give a reason for the TSB. Will this be enough?
Thanks

Al

 

The TSB I took in was for my faulty check oil light/oilpan replacement. All they had to go on was my telling them about the misfiring and recent crappy mileage. If they find a misfire code, they should replace the plugs.

 

Ranger,
So I guess my CEL needs to be on? Not the misfire? I'll let them know about the misfire and recent poor mpg. Althogugh I've had a solid 19mpg, I'll fib to get the plugs. But your right, they still have to find a misfire code.
Thanks
Al

 

Al,

My CEL never came on, but I did have a code. You might still have the code. My mileage is pretty much 100% city driving with really short trips. Only about 3 miles to/from work. My mileage would have been better on the highway, but I did experience a degredation of efficiency over time. I was getting around 18 for 100% city driving before it dropped and 24 highway (as stated!). I might have been able to get around 19 on a highway trip last week. I don't know what kind of driving you do, but your plugs might still be a bit fouled up. It is the short trips that really kill them.

 

So ranger... how does the car seem now with the hotter plugs? Have you had much time on them?

 

So far it idles smoother and seems to have a bit more pickup down low (it has been easier to get the rear to break loose). I went for a nice spirited drive this morning and throttle reponse was great. I am thinking my mileage is already improved, I'll know for sure when i fill up again.

The biggest difference I've noticed is that starting the engine cold is easier and it idles smoother.

Note on the low end power: This is after getting used to driving on fouled up plugs, I'm not claiming improved power over clean normal plugs.

 

Ranger,
Thanks. I'll get mine replaced as well and let you know.
Al

 

After driving on my new plugs and a reflash.. (very agressively I might add) I achieved an improvement of 3 mpg. (16.5 mpg) The improvement would have been more had I not redlined it so much and driven like a maniac... but I didn't buy the car for fuel economy. I think an improvement of 5 mpg wouldn't be unusual with tamer driving habits. (this was 90% city miles by the way)

Conclusion: The plugs and/or the reflash helped my mileage. When I was getting 13.5 mpg, I wasn't driving nearly this aggressively. I would recommend trying to get this work done on your car if you are getting 13-14 mpg.

Hopefully others who get this done will see similar improvement and post their findings here. I will post future tanks on here as well for a more extended look at the improvement. (more data is better right? )

 

Good info thanks and have fun.

 

Ranger... what about engine feel?

Anything you notice different about the power after the reflash/plugs?

 

This is really great information, please definetly keep us posted. I'll look into getting this work done with my first oil change if not before. So again you said you ran hotter plugs ?

 

racerdave,

I think the engine doesn't feel much different. Response is better.. it is easier to spin the back end out. No noticible power difference.. (except the easier to spin out bit)

CjsfastSS,

Yes I am running hotter plugs... per Mazda's advised colder climate setup. I think most of my improvement in mileage was due to the fact that the new plugs were clean and possibly due to the reflash. That's why I'm hoping others will post their results with varied pre-replacement or pre-reflash conditions.