Hello. I started having issues with my rx8, wondering if you could help me out. it's a 2007 6 port auto. about 70k miles on motor. since replacing motor I had an issue when it had a hiccup at about 4.5k rpm and did not have power until about 6.2k rpm. I decided replacing coils/wires/spark plugs. one of the coils was burnt off, but I also found a disconnected vaccum line from the uim to ssv/vdi/air pump solenoid vacuum chamber. I plugged the line back in, that fixed the issue with the power band and car would run like a champ but at the same time it started having problems on cold start (not as much on hot start but still noticable). I tried to reset ecu but did not help so I ran it like this for a week. yesterday I drove to the store, shut it off, when I came back to start it it would not start at all. I tried everything I could to start it, deflooded couple times and finally it did start but now it runs on 1 rotor and making puff puff puff sound somewhere below manifold. checked ignition and it's nice and strong. pulled spark plugs out and they are dry. compression is not the best but almost the same on 2 rotors so I dont see why only 1 would run. I dont know what to look for, my guess is the injector or ecu. did you see something like this before? would very appreciate the advice. the confusing thing is it did drive perfect before I shut it off, when I came back to start it in 40 mins this happened with this new puff sound. also car is decat. thank you!

 

Possible a spark plug wire came loose? Puffing sounds audible outside the engine point to compression escaping somewhere it shouldn't so.. loose spark plug?