Well I'll start out telling people that I did do some research on this but my luck i cant find anything out there

here is what is going on..i have a really hard idle on my 05 8 like feels like a misfire (i know thats not what it is but ill give all info)..the rough idle only seems to be when AC is on..could it be the car or would it be something in the AC some where..i didnt notice this when i got the car (almost 2 months ago) i did have the car for 2 days and AC went out and got dealrship to fix but noticed it just the other day..any ideas of what i might be able to do?

 

Check the motor mounts. Also a grounding kit helped with this on my car.

With the A/C on it feels like the engine "shudders" about every 30 seconds when stopped right?

 

no when ac is on and im idle my car shakes like a misfire but not a misfire but if ac is off it idles normal..i dont know im so cumfused right now im not sure what to try or do

 

My car has always done this. If your idle is perfect without your AC on, and it doesn't die with it on, I think you are probably alright.

 

Mine is like that, too. A/C is usually meant to drop temps a certain percentage and all the crazy heat across the country lately has had it working harder than usual. That thing is working hard under there and dragging things down and your idle speed with it. If it wasn't fully charged before it would not drag as much due to not being able to do enough work without enough pressure in the lines. Like Sam said, if it idles fine with it off and doesn't die with it on I would bet it is fine.

Also, I seem to be inadvertently following Sam in all the threads I check this morning.

 

^lol I get around sometimes. I also forgot to talk about how hot it is. rotary engines do not like 100+ weather. if you're running your AC it's working it's *** of for that and working its *** of to cool the motor down. it is a widely known fact that rx8's have cooling issues.

 

sweet thanks guys ill just live with it and if more things pop up ill get some answers again

 

I know this is old but I had the same problem with my 04, turns out my freon was just over charged. really put a hamper on the idle but after i let some out, all is well!