rough idle, rough ride
 

Hi there... firstly, a big shout out to the entire rx8 community! Awesome car, awesome handling. Got my hands on my own last month. Couldnt afford a brand new one ( In Malaysia it costs about RM300,00) so got hold of a reconditioned unit which was about 180,000. Its lightning blue, a real head turner!

So, problem started upon purchase actually. The car idled rough. Its idling at about 800, but vibrations in and outside the cabin is annoying during standstill especially when the air-con is on. Checked it at a place over here. Cleaned the air filter, changed the plugs n oil, added a treatment oil (ATF) for the transmission. The guy while cleaning the fuel / air mix unit, the thing in between the air filter and the engine fould a tiny hole going through the buttefly-like assembly? Is that a problem..

Prob 2. The ride is rough. very bumpy. Its on Bridgestone Potenza low profile tyres and stock Mazdaspeed suspension.

Oh, mine is the manual transmission 6 gear model...
MILEAGE 17,000

rEALLY APPRECIATE IT IF SOMEONE COULD HELP ME WITH THIS PROBLEM.
tHANK YOU

Rough.....
 

For the engine vibration, check the motor mounts. They have been known to collapse, and it's a cheap fix.

For the rough ride, ensure the pressure isn't over 32psi, if it's still rough the best solution is to get rid of the Bridgestones.

For the rough idle, check the system is still stock, if you don't have the big flat stock filter, that could be the problem - is there a cold air cone type filter installed?
Check for air leaks, check the clamps around the throttle body are tight, check the three hoses from the throttle body to the engine are all in place. Check the little fitting right below the butterfly (the hole is normal) make sure the hose is on, and not leaking. Check that the two fine screens are in place before and after the actual MAF sensor (you'll be surprised how the idle suffers when they are removed.)

Check? :mdrmed:

S

thanks... but problem persisting!
 

Thanks stealth...

yea, its the throttle body which he cleaned. He said its common for rx8's to half rough idling with a dirty throttle body. so he cleaned it. tHE BUTTEFLY-LIKE assembly inside the throttle body is gold-ish in colour, well-fitting with a hole through one of the leaflet. very tiny about <1 mm... but through n through. I was standing by his side to ensure it was well fitted. All tight. He claims he did an rx8 before n that had a throttle body with no hole in the throttle body and claims it could have been drilled though to allow more air in to raise the idle rev. izzit true?

I checked the tire pressure. 32 PSI! still rides like a bullock-cart through gravel. haha! Gosh, my old 850 Volvo GLE weighing in at 2.5 tonnes gav a smoother ride. This is unbearable! The brigestones tires are stock from the manufacturer arent they? Please advise....

Oh, another thing. There is a wierd noise when I lift my leg from the clutch on idle.... foot down, Only the engine sound is audible. Leg off, a new additional whirring noise sets in.... and when I switch to 1st or 2nd gear from a higher gear when slowing down, I get a whirring noise for about 1-2 seconds n it goes off after. Engaging 1st and 2nd gear also makes a kinda mechanical engaging noise that is only audible but not felt on the gear shift.... Any idea?

oh yea... its a stock air filter. Pink flat one

The noise you hear when you let up on the clutch pedal is the throwout bearing and that is normal. We all thought the same thing after the initial break in period when it became louder. It is said to be caused by resonance that the Renesis produces and can be heard at idle.

It sounds like the springs could have been replaced, what color are they?

hi there.. thanks for the comment. Btw, which springs are u refering to? The clutch springs between d flywheel n the clutch? Havent been able to get a glimpse of them cuz they workshops over here r too darn lazy to open up the assembly unless I'm sure of changing the clutchplate..
Are you certain the noise I'm getting is the same as the one u r? Resonance is when another matter vibrates on the same frequency as hte moving part iznt it? This sound like a moving wheel or something. Any ideas?
Extremely grateful for the suggestions so far....

The springs I was referring to are the suspension springs that could have been changed to aftermarket springs and give a stiffer ride.

The noise the clutch gives is almost like a grinding when the clutch is not engaged.

Yes that is a good definition of resonance. The clutch plate when disengaged is pressed against the flywheel so that could be why it sounds like a moving wheel.

yea.. its kinda like a whirring cum grinding noise which disappears when I engage 1st n get the car movin... pretty annoyin noise considering the engine is pretty silent. Any hope of reducing/losing the noise? Appreciate the advice

I haven't heard of a perfect fix for it.

Switching the transmission over to synthetic can help a little bit.

The throwout bearing should be replaced the clutch is replaced. ;)

i have rough idle after i install AEM Intake....what should i do ? clean filter ?

my car gives a rough idle too do u have to remove the engine mounts to see if they are worn because i checked em n i couldnt tell also what would happen if you put trailing on bottom and leading on top lol i confused my self now which way do they go????

I know this is old but I am new to the 8 community and have been working tirelessly to fix my idle problem. I cleaned the throttle body(even though the bottle said do not use on rotary's but i took precautions), now my idle is fine. The only other problem I am having which I am not asking for research, is my gauge cluster flicker on and off!!!!! Since I cleaned the throttle body I has not done it but it has only been one day. Im guessing I have a bad ground somewhere or my battery cables have a problem I know it is not the terminals because I bought new ones and cleaned the posts. Anywho! thanks for this.

Throttle body
 

Anyone know where I can go to get my throttle body on my RX8 cleaned?