Rough Idle due to broken engine mount
 

Hello guys,
I'm having idle fluctuation problem so I went to the dealer today.
And I was told that it is due to the broken engine mount.
Could this idle problem be possible due to the broken engine mount?:scratchhe
I think factory engine mount is too weak. I have changed 3 times in 2 years already and I don't even drive it hard.
Anyways thanks for reading!:)

yup, the car will vibrate very heavy and idle like crap, if u can budget 300$ id just go buy mazsports motor mounts that are suppose to be 100x stronger, if not just get another set of oem ones covered by warrenty

Yeah, they seem to wear out and stuff, even multiple times during warranty in some cases. I also noticed, at least at my dealer in my situation, that they weren't really checked on cars getting new engines.. and thus resulted in issues later.

This time I will just let mazda to install engine mount because it's covered under warranty. For sure, next time I will definitely go with the Mazsports motor mount.
Thanks for comment guys

Last friday, dealer test drove my car and they told me the mount was problem. They replaced the engine mount under warranty. But I still have that rough idle. No power loss but still engine idles crappy... What could be the cause if it's not the engine mount? I've seen another member having same issue and he got it fixed by new engine mount with bracket but I still have this rough idle. Any suggestions, thoughts would be appreciated!

Mileage/history?

How old are your plugs? If they are due to be changed they are easy to do yourself.

Do you have the stock intake with air screens in place? Removing the screens on a stock airbox or aftermarket intakes are common to cause crappy idle.

Have you ever cleaned your MAF sensor? Search the DIY section.

Only other thing I can think of is low compression, and you might have a long crank when hot if that is the case. If so, have it checked out before you run out of warranty.

I'm on my third set now. Big difference when they change them, smooooooth.

Mazsport designed these to replace the factory mounts that commonly fail. These are custom made with heavy duty steel and are more reasonable priced than the weak factory parts. Available in standard or *modified height if desired, please specify modified if desired when ordering. Includes installation hardware and grommets. Improves stability and reduces engine twist commonly associated with weak factory mounts. Steel construction guaranteed to last forever, rubber grommets are considered a wear item and are available separately. For Mazda RX8 Only

*Modified Height difference is 3/4 of an inch.

basically what i understand is theres 2 versions 1 is bulkier for FI applications then they make a version for NA, both are supposed to be unbreakable

How rough is the idle, my car rumbles and vibrates a little bit, hmm, how can I tell if they are shot, pics?

I believe the benefit of the modified height set is to make more room for the turbo but do not hold me to that. I know Scott has a good reason for the modified height set.

It's 58000 miles and spark plugs were changed in last October. But I don't think coils have been changed at the same time.
I don't have the stock air intake but K&N Typhoon big intake with no air screens...
When I bought the car, there was no air screen.
I should try to clean MAF sensor.
Should I get the OEM air screen since it can be the cause of crappy idle?

Thanks!

Normally, it drops from 1000 to 900 rpm and vibrates a little bit. But, sometimes idle is very rough that it fluctuates between 1000 rpm and 400 or lower rpm. When idle is rough, it makes whole car vibrates..

Same rough idle here too. RPMs drop to about 800 or so and shakes the whole car. 2004 with 48000 miles. Just changed the cat (it was toast), new coil packs, decarboned, computer reset (all done myself) and it didn't really help. Its a lot peppier though. Haven't had a chance to pick up new plugs and wires yet. I looked and didn't see anything obviously wrong with my engine mounts. What exactly would I be looking for if it is "broken." Anyone have a pic?

When the engine mount collapsed, you can't tell the different while they are still mounted to the engine. You will need to remove and inspect them. Even if there is no visible sign, the internal center rubber that act like a membrane separating the top and bottom chamber would have been torn and this would allow the vertical movement more easily; You have to apply pressure to tell the different between a good and a bad mount. I forgot to took a picture of the internal torn rubber. Once this membrane is torn, you may see sign and the external rubber start to break down, depending on how bad it torn, you might not see it until it is 100% collapsed and oil start to leak from the mount. This is how my passenger mount look like, worn to the point that if you literally apply some force you can twist and pull the mount metal out easily:
https://www.rx8club.com/attachment.p...1&d=1211579925

With AC on, engine idle rough and the engine start to shake then you hear some banging metallic sound coming from the engine/transmission, this is a sign/symptom of bad engine mount like mine; my PPF is hitting the metal piece in vertical movement.

Regarding to idle roughness, coil & wire & MAF might be the contributor. When the coils about to go and they are hot (engine running for a while) you can use the ohm meter and measure their resistant; most of the time, they would fall below acceptable range, but when you check the same coil again after letting it cool down, the resistant are in the acceptable range. This explain why I had a fried (yes FRIED, smoke come out of the engine bay) coil at the track once.

When my car had the rough idle, the RPM bound between 1k and 700 and vacuum usually drop to the lower range 15 to 20 Hg. This often happen when my AC is on.

Fortunately my car still have good vacuum in the 20-30 Hg range and it had 70k+ miles, so replacing the coil, ignition wire and filled the mount with 60A urethane solved my rough idle problem. Hopefully it will last, crossing my finger for now.

you haven't felt rough until you install aftermarket mounts, just get the upgraded OE version

it's almost always the RH side that fails

https://www.rx8club.com/series-i-tech-garage-22/failed-rh-engine-mount-pictures-128423/

Upgraded OE.....check. Are they easy to replace by jacking up the car?

Is there a service manual for the RX available for download anywhere.....same ones the dealer mechanics use? I have been able to fine them for all of my vehicles so far, but not the RX.

I thought mine was bad, that is worst. How did I missed that thread :eek: I must be in hibernation