Check engine and rough idle on cold start
 

Hi guys

I've looked through all the threads but as usual none that exactly match my problem pop up.

Ok here goes:
04 rx8
47000 miles
190bhp
Manual

I baught it about 4 months ago, in the past few weeks she has been getting some rough idle problems from a cold start. On a cold start the engine rough idles from 1 to 2 k fairly erratically and the check engine light comes on and off about twice untill the engine warms once she warms up everything is fine no check engine light and the power seems to be fine.

I've read on other threads that it could be coolant leek but I'm not seeing a huge amount of white smoke. I need to take it to a garage I know that much I just would like to be able to direct them so they don't try to bulshit me.

Any solid ideas would be great or things I can do to test for any of the suspected problems.

Many thanks,
Owen

LOL really you didn't find a single thread that was about rough idle?

Flashing check engine light is always a misfire.
https://www.rx8club.com/tech-garage-...t-here-222280/

Coolant leak???!?!?!?! ummm no

When was the last time the coils and plugs were changed?

That's were I would be starting.

Other cheap as in free things to do ...
Clean and reset ESS
Clean Maf
Check air filter
Search --> like this on google but without the quotes "site:rx8club.com rough idle"

Hi wcs

Many thanks for yor reply I did find many results on a rough idel but none that had a rough idle from cold start with a check engine light that turned off once the car warmed up many that were like it but none that were exacting.

Ok thanks for the info I'll check those.

i have the same problem let me know whats up

it could in fact be a very small internal coolant leak but i wouldn't pull your hair out just yet. as suggested check the performance of the ignition system first followed by servicing the major components that the engine uses for fuelling.

mark and check the coolant level over the span of several weeks also while checking everything else.

mmm Interesting

i suppose you don't believe it, but the renesis does still exhibit the same symptoms as the earlier engines when a coolant seal is just beginning to fail. fouling out the ignition on cold starts as the coolant is burned off after several minutes of run time.

I believe you.
Thanks for the extra information

I've been having some rough idling issues with my 07 6AT
I noticed that when I'm in D during idle, the car vibrates quite a bit, this is with the A/C on.
When I turn off the A/C in D or switch to N with the A/C on, the vibration lessens.
I have changed my engine mounts about a month ago but I'm still getting this issue.
I also replaced my plugs 10,000 miles ago. I change the oil out every 4000 miles.

What could be a possible cause of this vibration and what solutions are available?