I;ve had an ongoing problem with rough idle (particularly when warm) and some slight hesitation when starting. The dealer here in Adelaide initially told me that the coils needed replacing but new coils hasn't fixed the problem and they are now going through a series of tests suggested by Mazda Australia, including a compression test, which will be done early next week.
I'm starting to feel very nervous about what I thought was a minor problem. I have a 2004 model with only 40k (and regular scheduled servicing). Any ideas?? I'll re-post when I know what is going on.

 

did they look at the spark plugs or check the engine mounts?

 

Yes, the engine mounts have been checked (and were previously replaced under warranty). Apparently the spark plugs are also on the list of items to be checked next week.

 

Did you carry out the hard starter recall from Mazda?

 

Yes, that was done a couple of years ago.

 

you obviously havent ported your engine have you?




*brap, brap, brap, brap*

 

If the car run smooth it is unlikely the seals, but compression test will not hurt.

I pretty much think it is the spark plugs. They really have to change them way before 60000km. I am onto my 4th set of plugs man, and I am only on 53000km.

 

Everything is stock standard (no mods of any kind). There have been no other symptoms - it runs fine - no loss of power, no change to fuel economy or oil consumption - just the roughness on idle when the engine has warmed up. I'm hoping it is just the spark plugs.

 

It may be an obvious question but.

Do you warm the engine when cold & if so for how long........??

next, dont believe what the dealer tells you about spark plug life. The Stealership guys will tell you they are good for near 60k but if you have 25k or more on them, I would be changing them for sure.

REgards

 

I don't drive it hard at all until it is completely warmed up (and even then I don't really drive hard at all) but then again I don't let it warm up completely before driving off either.

 

I reported the same thing to my dealer, they found the motor mounts were worn and replaced them. But more to the point, the car was getting hotter they it should due to a failed cooling fan problem. I'd suggest pull the battery and intake and make sure both fans can move freely. A common problem is a rubber grommet from the intake dropping into the fan housing.

 

Well after much testing, including plugs, coils, leads etc. etc. my car had a compression test and guess what - it is low.
Mazda have agreed to replace the engine under new car warranty (even though the warranty expired 12 months ago).
As I said the only symptom I had was rough idle when the car had warmed up. It makes me think how many others may potentially have this problem. My advice is if your car is not running as it should and the simple things have not fully resolved the issue - get a compression test!