04 manual, 67k miles, original engine, AEM CAI. Owned for a year, never had a CEL, no major issues. A few weeks back, I started having some idle problems with the car, cold or warm it was the same. I had some small "coughs" coming from the exhaust that I could feel in the car, along with idle kinda shuddering at times, and my idle seemed lower than usual, around 750-800rpms. I replaced plugs, coils, and wires with NGK/OEM, (old ones looked like they were original factory parts, never been changed, sigh...) So this seemed to fix the coughing from exhaust as I figured it would, but nothing else. I reset the ECU by disconnecting the battery, and tried the 20 brake pedal stomp. This seemed to improve idle slightly, but its nowhere near 100%. Along with this, since its warming up outside now, I notice that my AC is cycling back and forth from blowing cold air as it should to blowing warm air, sometimes even hot. Occasionally it works properly, but more often than not, it doesn't. As I'm reading threads about the idle issue, I notice a post by Swoope linking a thread about my AC problem. Wasn't any description of why it was there, just the link, but from my research the man knows his stuff. I tried pm'ing him, but I guess I'm just impatient, sue me. In the thread he linked there was talk about the Recirc-reprogram for the AC unit, but that was about the only solution offered, and that was mainly for making the AC blow colder. (BTW, my AC line is already insulated, looks factory and not completely covered, just sections of it.) Anyway, Even if I tweak these things to make my AC colder, it still doesn't solve the idle issue, but it makes sense that the two could be related, as if the AC unit is malfunctioning and displacing power that could affect the idle RPMS. Just wondering if anyone had any insight on this, or links to anything my searches cant find. Thanks.

 

Im unsure about the A/C aside from a few things that could cause the blowing hot air. How old is your coolant? How long has it been since you've flushed it OR your heater core? Have you re-soldered the circuit board that controls the ***** yet? As for the idle, if you have brand new coils plugs and wires, did you clean your MAF? ESS? Air filter been replaced recently? Idle issue's can be many MANY things. As you check these off im sure more will be put up. Any Codes at all?

https://www.rx8club.com/series-i-tro...elp-me-223349/

https://www.rx8club.com/series-i-tro...-power-233257/

https://www.rx8club.com/series-i-tro...h-idle-228398/

https://www.rx8club.com/series-i-tro...h-idle-236385/

https://www.rx8club.com/nw-rx-8-foru...roblem-232500/

 

Do you have a problem with the AC?

If your problem is a rough Idle when the AC is on, but when it is off it idles smooth, then it is probably your motor mounts.