Idle Vibration Question
 

Hello everyone,

I am new to the site and I did a fair amount of research regarding this topic, but I still wanted to see what people with experience with rx8's think.

I am most likely going to buy a 2005 Mazda rx8 with 75,000 miles given that it gets the approval of a trusted mechanic :)! It was very well maintained (I think) and the carfax shows its fluids were changed and recommended maintenace was performed at least every 5 months the car was owned (1 owner, btw).

My question is this:

It is a 6 spd. manual transmission; while the car is idling, the shift knob vibrates. It vibrates enough to make my hand shake if it is resting on the shifter during idle. However, as soon as I step on the gas, it immediately tightens up and stops shaking. I can still feel very slight vibration, but it does not shake at all.

Is this normal?

I am used to a BMW 530i's 5spd manual transmission and it does not do this, so I wanted to know what you guys thought.

I am aware that the engine mounts, coils, wires, plugs, and even the MAF sensor can cause a "rough idle," but I do not know if a shaking shift knob qualifies as idling rough, or if it is just normal behavior from rotary engines.

Thank you for your help! Im sorry to ask what is surely considered an amateur's question, but I am new to the rx8 realm.

Motor mount.

The place I am looking at the car insists that the motor mounts were checked upon the car coming in...also I was told the car would "buck" and maybe "thump" under hard acceleration if the mounts were bad. I did not notice any thumping or bucking while driving it.

Does this mean that your rx8's shift knob does not shake?

Knowing what is actually going on here is really important to me. I do not want to buy a car that may have issues, so all your help is appreciated!

Just looking to find out how your rx8 idles and if the shaking shifter knob is normal, or not.

My shift knob does the same thing. It's a 2004 with only 34K miles on it (also previously a one owner car).

some shaking is normal
but very rough vibration is not

The vibration to me is nothing out of the ordinary. Car has no hesitation in acceleration in high gear at low RPMs which could be a sign of failing engine mounts and the idle doesn't seem "rough." Idles at 650-700RPM consistently.

+1 on the motor mounts for sure.

Anyway, mine shakes when on idle, and i needed to change my motor mounts. I hope it is still covered under warranty. It's an 05 with 32k miles on the odometer. I may have to call the dealership to find out if it is still covered under the warranty. I hate that shaking feeling...lol

seriously monchie?

you are spewing your mis-information and pointless posts across every thread you can find, and don't even know enough about the RX-8 to know what is and is not covered under each of the different warranties?

Don't worry, feel sorry for him as a Fat Chick sat on him and his brain hasn't been right since.

I've been in favor of the theory that his brain stem has a cut spring.

I'm inclined to think that it's just the direct-linkage nature of the transmission?

Yours shakes for the same reason it dies on idle-return in warm weather: You have a low compression issue.

Oh yeah...

'bs1532', I also think it is the motor mount(s). The original owner of my car provided all receipts of services for my car and his right side motor mount was replaced by IRVINE MAZDA at 63,967 miles.

Another possibility.
Since it is used, they removed the insulaton pad in the shifter boot making it vibrate allot worse.

The cut springs thing has been wore out. Every post he makes someone's on him about it. Learn to ignore.

Similar to the one pictured in this link: Filling Transmission Fluid Through Shifter.

thanks for your replies everyone. i decided to not buy the car. i believe there is an issue with the motor mounts now as well, and the dealer would not pay attention to my concerns about it, so they wont get my money haha.

Tell the dealership...fix it or forget it.

Anyway, you did the right thing. Good luck on your search.

I know, it's getting old.