Lately, my car has a more rough idle than I've ever noticed. Today, when running through the gears, the 'check engine' light came on, and then went out after about 5 seconds.

The manual says that the check engine light could be a loose gas cap or an engine electrical issue. I know that the coils are suspect on RX8's, and wondered if this is an early warning sign that the coils are going bad.

 

Do you know how long you've been on these coils? Other details about the car would be helpful as well. I know that bad coils can cause a rough idle but so can a bunch of other things.

 

You need to scan the car to see if there are any stored codes. There is a testing procedure for the coils in the FSM. Your issue could be many, many things. You just have to troubleshoot. Start with checking all the electrical connections and grounds. Then check for vacuum leaks.


Sometimes if you look closely you will find something obvious.

 

as has already been mentioned, you need to have the code scanned. Many auto part stores will do this for free.
once you have the code, let us know what it is or better yet, check the Sticky thread with all the codes listed for an explanation.

Coils are hit or miss. some people go through them quickly, others get 70,000 miles out of theirs.

 

There is no tried and true method to say "yup, those are the coils going bad on you" that doesn't involve getting a code thrown or taking them off and testing them one by one.

Rough idle can be caused by many things non coil related
engine code needs to be read to find out what it is

Start with the code then depending on what it tells you start working on the rough idle.

 

Original coils on a 56,000 mile '06. Slightly harder starting today, too.

Will run a scan and report back.

Thanks, guys.

 

You could also take the dealer approach to things and just start replacing parts until the problem seems to go away.

 

First, I want to report back-in that a really good quality OBD2 code reader is on sale at Harbor Freight for $89; usually, it's $159. You can hook it into your PC and download data, too.

Mine spit a PO301 stored code, and I replaced coils, wires and plugs and the car is running fantastic; quite a difference. Thanks to everyone for their input.

While changing the parts, I also cleaned the air filter in my Racing Beat intake with the ram-air duct. If you have this set-up, I strongly suggest that you remove the filter and clean-out the air box. Mine had a bunch of stuff in it sucked-up throught the ram-air intake.

 

^ Thanks for the info.