Two Questions
 

First, in the past two weeks my MPG has gone way down. My driving style hasn't changed, and I am not one to let the car sit much even tho it is cold out. Could this just be the car running rich with the cold (-3 to 20) weather or should I get it checked by mazda?? I have noticed she is is peppier and a friend of mine who I hadn't seen in a month said the car sounded a lot more mean. To put it in perspective, I used to get upwards of 300 miles or so a tank, now I barely make it to 200 miles.

Secondly, I did a search and didn't come up with much. My rear seems to be sagging a bit, my muffler has scrapes on it and such and with 2 105lbs girls in the back I can feel it hit the bump stops. Has anyone else had this issue, the mazda dealership said everything was normal and then said I have been bottoming out in the back a lot, the whole reason I brought it in. I am getting ready to right a letter to mazda about this before something gets damaged. Worse come to worse I will order the RB spring set if they won't do anything.

Thanks in advance, Mike.

PS: I only weight 175lbs

I think the cold weather among a few other things will have your car burning more fuel than normal as i've myself seen it in previous cars as well as the RX8. So wouldn't worry too much about it unless you were getting that kind of mileage during spring where temps are 50F and above.

Don't know about your suspension, maybe you blew some shocks?? How many miles on your RX??

Ya I suspect the cold for the MPG issues, and winter fuel is a bit different mix. The car has 29k on it so it shouldn't have any blown suspension. How could I present this issue to the dealer?

Miles dont determine whether you have blown shocks or not, Shocks go bad by the way the car driven, where its driven, the roads and conditions, etc. You might of hit one bad pothole or whatever, and you could of had a shock blown out then. In addition, there are some shocks that go out prematurely but with 29K. I dont think its unacceptable for a shock to be worn at that mileage (aggressive driving or city driving or a combo of factors).

Just have it checked out again to see if the shocks are rebounding correctly. or maybe something else is lose in your suspension...control arms, tire rods, bushing?? or have tech ride with u to see if they can pinpoint the prob for u.

Cold => denser air => more fuel used

on your sig.....you're putting a 13B in a Delorean???

we need a thread on that!

You are not yet at the end of the warranty, yes? If it is still under warranty you should take it in.

You should also prepare yourself not to accept any nonsense or overlong delays. e.g.: the ass dragging on the ground at 29k miles is not "normal wear."

lol ya that is the plan so far, but I have been considering a Northstar V8 also.

The MPG isn't that big of an issue really, the 7 only got 14 for a while, I didn't care it was worth the money for the feel and fun of the drive. I will have them check over my rear suspension. NH roads could have messed it up, but I would have thought I would see something in the front too, but they are rock solid in comparison.

If you get RB spring , replace the rear shocks too,

I have a set of rear RB springs for sale.

are you saying this because of differences with the spring heights or just because it's a good idea while it is apart?

Cold weather can reduce mielage by up to 20% for four reasons;
Winter gas
Cold weather fuel enrichment during starts
Higher air density
More traffic tie ups

My '04 seems to be easier to bottom at the rear than my brother's '05. I'm thinking of replacing the suspension soon anyway with RB springs and Dspec adjustable shocks.

Hmm, I wonder if mazda changed the spring rates or something between 04 and 05-present. huh.

More weight = less mpg

The MPG is with just me in it too, I am going to check other factors like air filter today. The weight came in about the rear bottoming out.

What about something as simple as the air in your tires? Pressures plummet with lower temperatures.

TPMS would bitch were it that low. It really sounds like worn springs. Though I don't know how the hell they wore out in just 29k miles. Is there a trailer hitch on the back of your 8 by any chance? :lol2: Hauling granite around up there? :scratchhe

lol, if only it were that obvious. I'll go by the dealer and ask them to check my springs again.