2004 RX8 has power problem
 

I just purchased a 2004 RX8 that seems to have a stutter when it gets past 4000 RPM and I searched the forum and it looks like it could be the coils/plugs or the cat?
I am looking into ordering the coils and plugs since I am in Canada and they are very over priced here.
The engine seems to rev fine till 4000 and then stutters randomly and sometimes has the engine light flashing, but it doesn't stay on to let me read the code.
And after a long drive at night I looked under the car to see if the cat was glowing, but it didn't look red at all.
And I also have to ride the starter for an extra second when I start the car.

Am I on the right track here with the coils and plugs? Is there a way to test the coils before I order new ones?

The car has 65000 KM on it.

Also does onlinemazdaparts.com have spark plugs too? I cant see them on the site and I am looking for a site that ships to Canada and has both plugs and coils so I only have to pay one shipping fee.

Yup it could be the coils/plugs or the cat?
You can get a timming gun.
Connect the ground wire from the timming gun to the battery.
Connect the timming gun wire to the spark plug wire.
Point/shoot the gun at the hood and see if the light is blinking steady.
Test each wire.

Sounds like the starter is the og aka old one. Get the updated starter.

This part of the post is what trubbles me, when I lost my engine on my old 8, this is what happen. It went into limp mode and I could not go over 15 mph or 3k to 4k rpms and sounded like shit.
I hope its just your cat not your engine.

Options are up to you. You can buy the stuff check the coils and replace them and what ever needs to be replaced or tow into mazda and have them check out your engine for you.
Depends on what you want to do.

With that many miles/KMs your coils are likely to be weak if not shot, totally, if you have never replaced them. When that happens, your cat also starts a slow decay, as well. Although it may seem expensive at first, BHR has a coil upgrade kit that will allow you to not have to worry again about coils being a problem. The kit is available with discounted spark plugs and we do ship internationally.

http://blackhaloracing.com/products-...tion-system15/

That's a great diagnostic. lol

Well my coils have shipped from onlinemazdaparts and I had to get the plugs from ebay since it is hard to find a site that ships plugs at a good price to Canada (I hate having to pay 2 shipping charges for both items but its still a hell of alot cheaper then getting local)

I am thinking of just gutting the cat since I don't have any emission testing here, any real downside to this? (besides the enviro... I know I know)

If the coils and plugs are bad I think the cat would be in bad shape too...

Well the coils arrived very fast so I just installed them and cleaned the throttle body while I was in there and it made a huge difference. There is still a few misfires but I think those will be gone when the new plugs arrive.

All of the coils had some white marks on the backside.

And the car starts alot easyer too.

So new plugs and it will feel like a totally different car.

Took off the cat today and it already had some larger pieces broken inside of it and other parts looked melted so I busted the rest of it out and man it made a huge difference.

Now I just need the plugs and it should be all good to go.

My starter does the same thing. I have the original starter in my 8, so just get the upgraded starter and you should be good. That is next on my to-do list for my 8.

Mine is starting fine since I changed the coils

Once you turn it off, do you have to wait to turn it back on or can you get it to start right away?

Starts right away