Hello All,

I am currently having rough idle problem with a 2005 RX8 GT Automatic which I bought a few months ago.

I was first having very rough idle about 3 weeks ago and I took it to the dealer and they said it needed motor mounts because they were completely worn out. (At the same time they were repairing a CEL which needed the catalytic converter and rear oxygen sensor replaced).

So, $700 later, the mounts were installed and the car idled as smooth as silk up until about 1 week ago. The problem is not as bad as before the motor mounts were installed but its rougher than when they were first installed.

Would the motor mounts wear out in a matter of a few weeks?
Is it possible that one of the mounts is faulty?

Any help will be greatly appreciated.

On another note, today I had to take it in for another CEL and they replaced the FRONT oxygen sensor. Another $700.

 

things like that couldve been diagnosed and fixed yourself and you wouldve had a lot more money in your wallet...

are you still throwing a check engine light? how many miles on the car? when was the last time the ignition coils/wires/ and spark plugs were changed?

 

No, the check engine light is now off since I picked it up today. The car currently has 106,000km and the ignition coils and plugs were replaced at 96,000km.

 

You might look under the hood in the dark and see if any of your spark-plug wires are arcing. They should be checked and if they are the originals should be replaced. Rubber gets very brittle when used in a HOT environment. Have you cleaned your MAF sensor?

 

I haven't cleaned the MAF sensor. What is the proper procedure for cleaning them?

 

unscrew the maf sensor and clean it down with maf sensor cleaner

 

Ok, finally cleaned the MAF sensor. It doesn't seem to have fixed the problem.

Any other ideas?

 

I had the same issue for a long time. I am pretty sure it was my ignition coils as the problem has been pretty constant but I haven't seen it since I put in the BHR Ignition kit [2 weeks].

 

Ok, I will check my ignition coils today.

 

I checked my ignition coils. They seem ok. They were changed about 10,000km ago.

 

How exactly did you "check" the coils?

Also, have you verified all the ignition wires are secured?
Pull one wire out at a time and reinstall it making sure you hear/feel the "click" in the wire boot.

 

I took all the coils out and they all looked fine. There was no discolouration or white spots on any of them.

 

White spots don't indicate bad coils.
Bad/shorted coils are not seen visually by simply looking at the housing.

 

Would this be considered a warrantied replacement if the warranty were still intact?

 

Well thats how I was told to check them.

How do you know if the coils are bad then?

 

First you can read through this thread where I helped someone else on using a volt meter:
https://www.rx8club.com/showthread.p...ighlight=fluke
This can tell you if the coil is bad, but can be difficult to tell if the coil is going bad.

But for you, it'll be easier to buy an inline ignition checker.
Basically, you install it between the spark plug and the wire boot.
Start the car and observe the timing light.
Do this for all four coils/plugs and see if one light appears dimmer or inconsistent with spark timing (or simply put, one doesn't look like the others).
Here is what one looks like:

 

I too am having rough idle issues. I just replaced the coils/wires/plugs which helped it run smooth while driving, but you can feel the roughness in the seat, and obviously a lot through the shift ****.

Quite a few people seem to suggest cleaning the engine with the mazda solvent/seafoam/water could remedy this. Although in my case, I'm also suspect of the motor mounts - just haven't checked those yet.