First, let me say I love my 8 - - just want to get rid of the chatter noise at low rpm. Issue has been present since purchase in early 2005. Long story short, have brought this up to my dealer several times with no fix. Stopped by to make an appointment - - service rep said they have been notified the noise is normal. Dropped my car off for some other work and requested the ignition coils be tested, service rep did not say it is normal (guess it depends who you talk to). Called me later and said the tech found carbon biuld up in the upper intake - - I approved the cleaning kit and they advised this will fix the problem because I wasn't getting a clean burn. Drove the car this morning - - chatter wasn't as noticeable but still there. Shouldn't the carbon build up be a sympton of the problem rather than the cause? I do readline the vehicle on a pretty regular basis and do not granny drive it. I read hear before that rotary god said the grade of fuel (premium vrs 87) should not be an issue. I seemed to have the chatter no matter when premium or 87 is used.

Any advise is appreciated.

 

is this sitting at idle. does it change if you press the clutch in? when is it present?

 

I read a post from Mazda Maniac where he said that noise was the AUX intake valves rattling, he didn't say if that was any long term problem.

 

not at idle, hear it with low rpm acceleration - - from standing start or sometimes at low rpm in low gears

 

hmm... so did they run any other tests on your car besides pulling off your intake and spraying it with carb cleaner? carbon build up in the intake manifold or in the intake itself? have you checked the issues problems section to see if there is any similar to your's? could be a synchro issue... maybe.. definitely could be a valve.. i am not sure at what point aux intake is used though. keep posted on what you find out with this.. if it is carbon build up you could sea foam it.

 

thanks for the replies. I have checked the site many times in the past for others with this issue and it seems to be somewhat common - - at least some others have posted. I have seen where the coil packs have been replaced and owners said it fixed the problem. I am more concerned now that they found carbon biuld up in addition to the chatter that I have noticed for a long time.

 

That's the problem I had with my AT, they replaced the coils at the dealership...supposedly...and the problem didn't go away. Not until I got my new engine was my erratic RPM at idle, that chittering sound, and a loud knocking sound fixed.

 

i get kind of a v8 rumble at low rpms. kind of. it wasnt there when i first bought the car, i think it started appearing about 6k miles ago. it also only happens when the engine is cold.

is that the same thing? is it normal?

 

what gears do you hear the noise the most? And what RPM range does it start to make noise? And what side of the car does it make the most noise?? And does it make noise when you are downshifting or giving it gas?

 

first and second. 1000-2500rpm. dont know. giving gas.

and it seems to have lessened or disappeared since my 30k service. it might have been just warm though.