My Rx8 is dying at stop lights, but only after running on the highway
 

First off, thanks to everyone that has shared info on this website over the past few years. This is my first post, but I have benefited very much from reading other posts since buying my RX8 3 years ago.

My 05 currently has about 56k miles and is starting to give me problems. Over the last 2 weeks, it has died on me 4 times....at which time it is immediately flooded. If I let it sit for 20-30 minutes, it will then start right back up. The 4 times it has done this have all been after driving on the interstate at 70-80mph.....then when I get off the interstate and come to a stop it dies.....but, not all the time. Sometimes, it's my very first stop.....sometimes it's my 3rd or 4th stop, and sometimes not at all. Once, it actually stopped fine, idled for a while, and then died when I pressed the gas to begin going again.......It has never done it after simply driving around town at lower speeds. My check engine light is never coming on, so there doesn't appear to be any sensors picking anything up.

The only other problem I've had with the car since buying it was about a year ago. The check engine light came on and the code indicated a sticking valve. My local Mazda dealer yanked the engine and replaced the intake manifold...luckily under the warranty.

Thanks in advance for any help that anyone might have!

Welcome to the club!

I would check your cat first. Also how old are your plugs & ignition coils? Beyond this I would get a compression test for your engine. It could be going bad, you never know.

Sorry for not being more versed....... my cat?

The plugs and ignition coils have not been replaced since I've owned the car, so they are at least 3 years old. I bought it from a dealership and the original owner only drove it about 25k miles, so they probably have never been changed........

Catalytic converter. It's in between your headers and muffler as part of your exhaust. It could be clogged. This could explain your problems.

Also if your plugs and ignition coils are that old then that could be it as well. In our rx8s our spark plugs only last 15-20k miles and the ignition coils are prone to failure within that time as well. It's worth spending the ~$200 every 15-20k miles.

Please give us the history on your car. The service it's had and parts replaced. Model, type of driving it gets(long commutes), fuel used, oil type and consumption, ever flooded, red lined. Just any thing that you can add.
You might have some carbon build up from a lot of short trips and not seeing the red line much. You might run a few cans of Seafoam, BGK44 or another carbon cleaner.

The only major service it's had other than regular oil changes etc is the intake manifold replacement I already mentioned. As far as type of driving goes....mostly short in town trips. I only use premium fuel, usually from Shell. I use non synthetic Valvoline oil. Yes, it has been flooded before, due to not adequately being warmed up before shutting off.....but that hasn't happened in over a year. It has never been fully redlined, but close. I usually let it run up to 8000 rpm almost daily when going through 2nd and 3rd gears as I enter the interstate on ramp, but I never keep it in the higher rpm ranges for long........

Valvoline oil is bad. you might want to switch it to another brand.

it feels like either you have sticky seal, or its just bad motor.

ask your dealership to compression test it. constant stalling after a long drive and/or on hot days means 90% of the chance that your motor is shot.

oh also you might want to tell him to check the Throttle body sensor(its inside), and compare it with factory spec. its easy. just plug the wds in.

Wouldn't a sticky seal, compression problem, or Throttle body sensor problem trip an electronic code and illuminate the check engine light?

Valvoline was the only non-synthetic 5 20 I could find......what do you use?

since you had flooded your car before and you haven't change your coils and plugs, I will suggest to change wires, plugs and coils.

yea start at basics, wires plugs coils and see how it goes.

*some* valvoline is bleh, i personally use their VR1 oils in my rotaries, seems to reduce carbon when i tear them down.

if the above doesnt improve anything we can go from there, dont wanna go wasting all my breath in one post ;)

kevin.

I am having the same Problem with my 04 66k. Has anyone had t his fix and where to start.

^start off with coils :yesnod:...my cars starting to do the same, and i know its my coils, but it isnt to the point where i dies, but the idles way weird

Yeah it idles crazy before it dies and once I get it started agian it doesnt die agian. I can drive around town and nothing once i hit the high way and come to a stop or i can even put it in nutral and the R's drop really low and then it cuts off.

+1 for Coils..

Had similar situation, and it was the coils. Just got my car back and it's good as new..

Def need change mine...runnin on 35k on orginals......stalled twice so far on a stop light in the one year I owned the car......should coils be changed when spark plugs are changed too?

^its recommended...its a really easy job, you can do em both coils and plugs urself

Does it have powerloss on the highway trip. Does it accelerate in 6th or does it bog when you floor it? If it bogs, if you clutch and redline the car, does it run fine again?

If so it's a carbon problem, probably from crap oil and/or poor quality gas.

Seafoam it when the engine is really hot ( redline it in the driveway some and let it get toasty ) and use better gas, and get some good quality oil in there. consider going up from 5-20 or 5-30 to something better.

Exactly what mine was doing at 22k when my engine was deemed bad.

remember, an engine is nothing but a piece of metal, it will NOT be able to tell you that "oh I am not feeling well".

sure it has a lot of sensors here and there, but the monitors are all pretty "passive", so it will detect a problem eventually, but dont wait until that day comes.

many people (including mine) throttle body went bad without any noticeable signs, your idle might jump around, but nothing that you would pay attention on.

Coil CEL? yes. but ONLY if your coil is like 99.99999999% dead. so yeah, it will be too late.


you should start replacing your coils and see what happens,

samething happaned to me, it was the ssv value that was stuck open.

Yeah, My car doesnt really lose power at 70mph and up in 6th. And what is a good oil to use. Im new to the rotory so i need a little help. Also what are good coils to buy and how much will they run.

SSV was not the cause.

it wouldn't cause your motor to stall.


You're new to rotary so yea you should go ahead and do your own homework, STOP ASKING PEOPLE TO SPOON FED YOU

all we could be is tell you what might be your issue.... JUST take it in to your dealer and get it tested to find out want is wrong with it. if you have to pay, so what... this way you know what needs to be done.

Homework! Its an Rx-8 not a math problem. I was simply asking for help. What do you think i am doing asking ppl who have owned an Rx-8 longer than I. I am doing my own homework. I figured I could get some heads up on what it might be. You however seem to know alot about the Rotory so insteed of blasting ppl in a Blog you might want to share some of your knowlege.

At night, take your car out. Beat on it for 10 minutes or so(high revs) after its warmed up, pull into your driveway, get out and look underneath to see if the catalytic converter is glowing, specifically around the o2 sensor.

The placement of the catalytic converter is pretty much right in the middle between the engine and the exhaust, look at it from the drivers side of the car. See if there is any glowing, faint or otherwise.

As long as you are under 80k miles, take it to the dealership and say that shit is glowing red, they should give you a new one. Especially if its been flooded or had a decarb done.