Mazda RX-8 hard start and low rough idle issue still unresolved on Mazda RX-8

Some Mazda RX-8 owners report experiencing hard start and low rough idle issues, particularly in models from 2004 to 2008. These problems may be linked to PCM calibration, as engine power loss and rough idling can occur in high temperatures without proper adjustments to oil lubrication and ignition timing. Additionally, owners often face challenges distinguishing between starting compression issues and ignition spark problems, making accurate diagnosis essential. Battery health is another critical factor, as cooler weather can negatively affect performance and lead to slow engine turnover. Issues such as idle hunting and jumpy idle may also contribute to rough idling, requiring a step-by-step approach to troubleshooting. Furthermore, lower than specified cranking compression can cause hard starting, and checking the battery is recommended based on service bulletins. Vacuum leaks, particularly after adjusting fuel trims, can significantly impact idle quality, necessitating inspection of components like the MAF sensor and injectors. Lastly, a failing starter motor may result in hot start difficulties, emphasizing the importance of ensuring its proper functioning. Addressing these factors systematically can help Mazda RX-8 owners resolve their hard start and low rough idle concerns.