I've had my rx8 since forever, and have supposedly had this issue fixed before yet ever summer my car is crap. When its hot out, after driving for a bit, the rpm drops to 750 idle and is either VERY sluggish, OR it just flat out dies and I have to do the defloodong procedure to get it to start again. Once going it'll be sluggish, then the HP kicks in and o can hear a rattling noise along with some kind of air leak while on the gas and after I let off the air leak persists for a bit then stops, and that happens EVERYTIME I'm on the gas after I drivdriver'se it around for a bit. Any ideas fellas? Cause the dealership said they have no idea and probably can't figure it out til they experience it in person....fml.

 

Put your windows down instead of using the AC? Does it give you any issues then or is it solely related to the AC.

 

you have a case of bad coils, mines did the same thing until i replaced them.

 

How many miles on the car?
It may be fuel pump or compression related. Even with a leaking A\c system you shouldn't feel more than little small vibrations.

How many miles have you got on the spark plugs and coils?

 

Car has about 41,000 miles, 2004 year model. I recently got Tue coil overs changed when I took it in a month or two ago to try to fix it... as for plugs, haven't changed them yet. And to the window comment, yes turning the ac off helps, but the car is still sluggish, makes the weird noise that sounds like there is a marble stuck in there clanging around, but it hasn't died on me yet with the ac off. And seems to idle better the few times I braved the heat with it off..

 

Err....the not Tue. Damn phone! I'm about 10k into a Mazda reman BTW, I should have mentioned that before but forgot >_<


On a side note, sorry for the jibberish I was speaking, auto-correct hates me. I'll be using my a computer from here on out since obviously my phone want me speek like ima chinamen.

 

I was just curious about the no ac thing to see if maybe the ac was taxing your car to much. I have had a car before that ran perfect but with the ac on it was not even close to driveable. If your at 41k and never changed the plugs it is way overdue at this point. When they gave you a new engine they most likely put the old plugs back in the new motor unless you gave them new ones.

You can search miac or marbles in a can and you should get lots of results for that, I think it has something to do with coolant flow and some part the dealer changes, but without searching myself I am not 100% sure.

 

it is your coils, i had the exact same problem as you. i replaced my coils and in four
months along with a long drive through las vegas they were shot again.
i now have a different coil system and no longer experience that problem.
like i stated it was my coils and i have fellow members here to vouch for my statement.

 

oh by the way my car only experienced this when temps were over 92
below the 90 temps it ran hard and strong

 

the a/c thing makes me think its a failing primary fan as per my experience:

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/mod-1-mizu-radiator-fans-mod-2-spal-fans-215539/

 

running the ac in hot weather makes the engine run hotter
so it still sounds like bad coils. when coils are bad there is
no power in hot weather, running the ac only makes it worse.
i went thru two set of coils before my problem was fixed.
im no longer using stock coils.

 

I saw a little bit of the same stuck in traffic early on. You probably have some pretty high under hood temps, sluggish is because the heat as well. There is a thread in my sig for your first $100. It has a cooling stuff, ignition stuff, grounds (maybe more important when things are hotter and looser) and then says plugs and coils. I would suggest running through that list. I had a fan that would not come on until I did the grounding work. As mentioned above, the high heat also screws with the coils. I have the version "B" coils, I think from Mazmart, they are going into their second summer without heat issues (in Florida).

Recommendation, do the first $100 stuff, then coils, then plugs.

Let us know

 

My car is doing the exact same thing. In cool weather it runs fine, when it gets in the 90's it starts to run hot but never overheats. Engine temp gets to 209 - 218 and then runs like crap and even stalls at stop lights. If I run windows down and full heat on then the temp gets down in the 195 range and starts to run good again. It seems to run best when the temp is around 183 to 186.

I am going to replace coils and wires to see if this will solve the issue.

I already replaced plugs and MAF. Replacing MAF did make the car run smoother.

 

^ Look at the cooling stuff in $100 thread. What I saw was that every part of the engine was hot, all intake lines, fuel, all air, everything. Coils, computer, sensors, the lot. One major issue was that the fans blew hot air back around and through the radiator and back into the engine compartment as even hotter air. That was also one of the cheapest mods in that thread.

 

Well I'll be! that's about how long its been since they were replaced, I haven't had a long trip to vegas but who knows.

I'll check out the $100 thread and have Mazda check the coils again (Taking it in again today or tomorrow for new rotors and evap pump)

My brakes sound like a damn public transportation bus, at first they said they "couldn't reproduce the problem", and all they did was resurface them, and although they have plenty of life left in 'em, they still make that sound. So they said the only way to fix it now is to get new rotors.

Thanks for all the help by the way everyone

I knew when I signed up for these forums years ago it was gonna be worth it

 

Gonna plan on doing coils plugs and wires this weekend, what're the coils you suggest I use scremn8? Do you also prefer certain plugs and plug wires? Anyone else have suggestions?

 

Shini, I suggest to clean your eccentric sensor. I did this and now my car runs awesome. I can't believe a little road grime and a small piece of metal on this sensor throws the whole car off.