Go to your local auto parts store, buy Marvel Mystery Oil(MMO), wait until a quarter tank of gas or less, add 6-8 ounces of MMO to the tank, fill up with gas and drive around for a little bit. It will cost you a couple of bucks. I had a rough idle when I got my 8 and premixing solved it. For under $5, theres no harm in trying it.

 

Hi folks. I just wanted to get completion feedback on this thread. What was the eventual result of the tests on your car NoOdLe BoY?

My car just started to act up today, and REALLY bad. My car does exactly the same things as mentioned above, except it goes 300-400 less than 1k!! I swear... my car could just stop running accidentally. Worse yet, each time the engine dips below 700 my battery CEL is flashed.

I will follow up after some tests today:
1. Clean filter, clean MAF
2. Reset with break peddle trick

If there is time, I'll try to identify and locate good premix.

 

You can borrow a bottle of Idemitsu from me....

Compression test time

BTW...you up for doing my car Saturday? I have to go to a concert at 6PM...

 

Please give us all the info on your car, year,miles, what service it has had, plugs, anything you can add.

 

well i put in some new BHR plug wires but they didnt help.

im kind of a noob but im thinking its either mazdas fuel mixture thats a bit off more than usual, fuel pump giving out, or bad compression.

every thing is fine when im driving but after a spirited drive it gets a bit more serious than usual. its wierd. and its botherin the crap out of me lol.

 

It's a 2005 model with 43,000kms
Racing Beat: Intake / Muffler.
Stock Coils
Stock plugs
Stock Wires

All service and tune ups done on schedule.
Oil is topped up as usual.

Two weeks ago I drove to Kamloops. It was a 42 degrees, and about 1 hour of incline (uphill) driving, at *above the speed limit*.

Also: It has been a very hot past two weeks compared to our regular local temperature. Today the temperature dropped considerably: currently 21 degrees... five days ago 42 degrees. (So I'm thinking maybe vapor lock?)

The idle is rough, but the rest of the range is smooth. It normally idles at 900 rpms, and this is fine. It's just that it's dropping down periodically, to below 700 and that's where the trouble starts. Lots of vibration as the engine chokes and almost dies. The entire length of time the IDLE rpm does not stabilize like it normally should at 900 - 1000 rpm range.

 

Hey guys, just found this thread: Rough Idle with AC
Might be the ticket. I'll try this tonight. (It's a free test)

 

Yup that pretty much solved it.

As I see it there was two problems:

1: The coils and wires and plugs seem to be congested (old).
2: The ECU was allowing below average idle rpm rates, where the first problem is MUCH more noticeable.

The problem was fixed because when I reset the chip (peddle) and unplugged the battery for 30 seconds, it reset to a higher rpm level. Very nice! so the second problem is fixed! and the first problem is not as noticeable anymore (still there though) - or at least the way it was before.

For these RX8 cars... seems like a must upgrade, are high end spark coils, long lasting spark plugs and high grade gold cables.

 

glad you found your solution!!

im gonna clean my TB in a few days when i have time. ill keep you guys posted.

 

i am having the same problems
i have a 2004 automatic rx8 and i am
getting rough idles i did change a few
things which are


-Ignition Coil (one of them were bad)
-Moroso Spark Plug Wires
-NGK Spark Plugs

and sadly the same problems i will try your advices
that are given above and let you know how it goes.

 

check the motor mounts