Azam1030

Hey all, so I have a 2004 rx8 with about 78k miles. While driving on the highway for about 20 mins, when I have to brake and slow down, the RPM needle goes down to the idle state than the car would automatically shut off. I would have to wait a minute or two before starting the car again and it takes sometime before the car could idle properly (The car struggles to stay on)

Does anyone know what the issue might be, I had two people tell me it might be the coils, any suggestion will be helpful.

hokie027

There are a lot of threads on this, but heres what you should look into:
1. Ignition components: Coils, Plugs
2. What type of intake do you have? You're engine could be starving for air...
3. Possible bad CAT.

Check that out.

OL!z RX8

iTrader: (1)

I had the same problem a few months ago...specially when i had the AC on, it shut off. Always when i came to a stop also, mine has 98k miles, and its an '04. I did a complete tune up to it and cleaned the MAF SENSOR, and now the car starts better and quicker and runs a lot better too, doesnt vibrate as much but when i have the AC on it still vibrates a little but it doesnt shut off anymore...so do a tune up if u havent done it yet and clean the MAF SENSOR.

Azam1030

Thanks guys, I recently change the CAT about year and half ago, I'm going to have the shop check the coils and do a complete tune up, hoping that will solve the issue.

Thanks again

stinksause

iTrader: (5)

could it be a vacuum leak? Check to see that all of your rubber hoses that are connected to the intake are not leaking/ are snug on on both ends ... does your car make a BOV whistle during free revs etc?

A vacuum leak will alter your fuel trims under constant load during cruising and when you stop, those fuel trims will no longer be valid ... therefore the fueling is incorrect and your car shuts off

Azam1030

I'm thinking its the coils, most people agree with me. I have don't hear a whistle noise when I rev the engine but I'll make sure to mention it to my cousins when he works on my car to check the vacuum as well.

peterlemonjello

Changing the plugs, coils, and wires is the best bet. Cleaning the MAF and air filter is good too.

Another possibility is the fuel pump. Although, usually when the fuel pump fails there's no idling issues.

hokie027

Hahah its funny I should participate in this post because now my car is being problematic. Whenever I fully depress the clutch to the floor--generally from going from 50mph or greater to a full stop--the RPMs go from a 1000 +-100 for a few seconds and then wildly goes down to 500 to a 1000 then drops to 0.

I decided to play some experiments on the way home noting this problem... if i keep the clutch depressed as I slow, then I stall out--and only the check engine and battery light comes on and the engine is recoverable by reengaging the gear. If I keep it in neutral with no clutch depressed then I get the quad light show as I slow and the engine dies. Lastly if I let the engine stop me by downshifting then I had no real issue other than when engaging the clutch if I took my time I faced the opportunity of stalling as it frequently got close to 0.

So here's what I have looked at. I'm installing my BHR coils soon, perhaps even like tomorrow soon. I took off my MAF and noted the sensor was dirty as heck, so I cleaned it with the CRC MAF cleaner, let it dry... took it for a drive still the same issue, then I removed the MAF to check it again and noted the O-ring is broken... and the sensor still looks dirty--so perhaps I get a new one. Will wait for thoughts on that... the spark plugs have maybe 6000miles on them, just recently installed them.

I did note the idle was a bit better when stopped after I finished installing my circle earth system yesterday; however, I was curious if that could have made the slow down issue worse? I have not replaced the CAT... I may take a peak at the honeycomb and see if it still looks good--if not thoughts on a BHR midpipe w/ Davesport or the RP SuperCat?

Thanks!

Oh its a 6Speed MT with 82,000miles on it and I keep it extremely well maintained.

EDIT--Simple Fix: Replaced the MAF, one of the wires in it was broken so a replacement solved the entire problem. Idles and drives far better!

Azam1030

So I have done a good amount of research on this issue. I have read so many opinions about possible solutions to this issue, from checking the coils (people are big fans of changing the coils, especially in this forum ), checking the CAT, Fuel Pump, and cleaning the MAF or replacing it. Also, I have spoken to others who have gone through the same issues, most have taken their cars to Mazda so their motors can replaced under the warranty. Unforunately, my car has a straight pipe so I would assume Mazda will just consider my car void under the warranty.

I bought a replacement MAF for my car and will be replacing the air filter as well.

To my amazements, there are so many people out there who have gone through this same issue with this car. I have owned this car about 1 year in half now and I have gone through so many issues, on average I would say every 4-5 months I am dropping this car off to a mechanic shop. I have decided once I solve this issue, I'm going to sell the car. Don't get me wrong, I love driving the Rx8 and physically it is a beautiful car but you get to a point that you just want a working car. I can't believe Mazda has release a vehicle like this in production with so many issues, this is just proof that Mazda does not care about giving their consumers a 100% reliable product.

stinksause

iTrader: (5)

I've had my rx8 for over a year now ... absolutely 0 issues, I just maintain it well (knock on wood) .... but I understand where you are coming from ... good luck with your search.

YeepsRX8

iTrader: (1)

I had this same problem. Only thing is my car shut off after the 2nd time and wouldn't come back on.

It's like everyone says.
1. Bad CAT
2. Coils/Plugs
3. Sensor

Now this could have happened for a couple of reasons. Does your car take a couple seconds to start up or does it start quickly? That was my issue and eventually the CAT died with everything else. Just get it to a stealership and checked. Like an $80 inspection and they'll probably tell you its something one of us said and charge some outrageous price.... Can't avoid it... lol

But good luck to you and hope all is well.

Charles R. Hill

iTrader: (7)

This issue is usually alleviated by not only cleaning/replacing the MAF sensor (as needed) but by also resetting the e-shaft profile and making sure the e-shaft position sensor is clean, as well.

stinksause

iTrader: (5)

or take it to a rotary shop like KDR, IRP or JPR ... they are all in your area. I would go 1. KDR, 2.JPR, 3. IRP in terms of my preferance

Azam1030

stinksause:

Talk to me after another year goes by

YeepsRX8:

I had my cousin check the coils and I recently replaced the cat, I'm still have the same issues though :/

This coming week, I will change the air filter and MAF, hopefully that fixes the issue, if not, than I will probably take it to one of the rotary shops (KDR, IRP or JPR) or a mechanic I know will be able to fix the problem but will rape me with pricing.

A mustang is looking so much better to me right now.

burn89

I had the same problem about 3 months ago.. whenever i stopped car would die, when i got home i pulled off my intake and the shop had overfilled it and it went up into my intake.. all i did was got some mass airflow cleaner and ran a bottle of seafoam while keeping my car at about 7.5k for 10 minutes and it fixed the problem.. been running great ever since

stinksause

iTrader: (5)

Azam, do you do your own maintenance or take it somewhere? I will definitely get back to you in a year ... especially since I will be turbo by this winter

But nonetheless, good luck with your car passion regardless of whether there is a rotary in your future

BabybooR33

well my 04 automatic rx8 has been gently whistling on lower rpms since i got it 8 months ago & losses power easily... especially if i turn the lights on, when the ac is on or loud radio the car shuts-off soon after... maf sensor & filter seem to be fine, replaced ignition wires & spark plugs months ago, now im going to try to replace the engine-belts & alternator ... if anyone has any solutions or advice plz respond, i would love to finally have the car running with no issues..

Azam1030

BabybooR33:

I would check the air filter by your intake (apparently mines was really dirty), also the MAF sensor might have something broken in it. If anything, I would just change the whole sensor (its about $80 bucks). From doing all my research, I've notice a good amount of time people would clean or replace the MAF and the car would run fine.

Azam1030

So after changing the air filter in the intake, cabin air filter and the MAF sensor, 20 mins of driving the car the rpm needle struggle to stay on 1000 rpm and went down to zero and it completely shut off.

So from changing the CAT, checking the coils and the alternator. My final conclusion is that it has to be the motor, I will drive the car 3-4 months more than be in the process of selling it. It was a fun car to drive but definitely a car that does not have a long life span and very high maintence.

Hopefully Mazda fix these issues in the 2006 - 2009 models

stinksause

iTrader: (5)

good luck man ... I hate seeing people turn away from the 8, but that's life of a rotary owner I guess

Azam1030

Well guys, it seems like I jump the gun. I guess my car had to get use of the new sensor, I drove it to NJ (35 - 40 min drive) on Saturday and drove the car all day today. The car drove better than before and it has not stalled on me once during the past two days.

I assume the car just had to get used of the new MAF sensor, I will keep you all updated since I know there are couple 8 owners out there going through the same issues.

BabybooR33

(2004-Automatic rx8)ok.. i finally replaced the battery, alternator, ignition coils, maf sensor, filter, belts & a belt pulley wheel that was making some noises(ignition wires+spark plugs replaced a few months ago) & the car starts up better & accelerates a little smoother/better, BUT 2-3k rpm engine whistle still persists & the engine sometimes almost shuts off when i come to a stop or red-light... anyone have any clues to what it may be? or im stuck with the way things are as long as it rides pretty decently..

Bluerenesis

I agree with this and its easy to do.

VATO

could you tell me where "maf" is located on car? I am not mechanically inclined.

DarkBrew

Likely answer
whistle = vacuum leak

Also it's possible that the o-ring on the MAF got pinched during install.