I finally got the correct spark plugs (NGK sent Advanced Auto 4 leadings plugs ) and swaped them out today. Car runs great. Not quite the power boost I've read from some people, but its a lot smoother, no shuddering, no unexplained drops in idle or when letting the clutch out. You can tell the car is back to 100%. OR IS IT??

Was driving around just to make sure everything went smooth. Was getting onto the highway and mashed it. But around 7K the car started to growl...not a natural growl like from an intake or exhaust upgrade. It sounded like a V6

Whatever it was, I didn't like it. So I got out of the high revs and went to 6th and cruised along. Car ran fine. It almost sounded like it was running STUPIDLY rich, but how? I got off the highway and headed home. I kept the car in low gear and tried to pinpoint the cause of the noise. Around 6K RPM I heard it again. But it wasn't really the engine. It sounded like something was getting smacked over and over and over again and got louder as the revs increased (kinda made it sound like a piston engine). I thought maybe the spark plugs were in too deep and the apex seals were hitting the tip, but then I'd hear the noise at any RPM.

Well on my last little straight away before I got home I left the car in first and let it rev up (VERY lightly) to about 6-7K RPM. Now the noise was gone. Parked the car and gave it a quick redline. Still no noise. Very strange. Has anyone encountered a similar problem before? Is it carbon build up being blasted away by the fresh plugs?



BTW whoever left the dark green RX8 with upgraded rims on the side of the highway, its still revving itself to death with nobody in the car

 

Could have been that the ECM had adjusted the mixture/advance for the "bad" plugs. It just took a little bit for it to readjust.

 

I thought it might be something like that, but figured it couldn't be that simple. I'll give it another drive tonight and see if its back to normal. I did reset the ECU yesterday trying to get rid of a bogus CEL and haven't redlined it since. Perhaps it is just relearning after all..

 

Drove the car hard today and all is well. It seems my ECU finally figured things out and the car is back to normal. Pulls STRONG. Turns out I did get that power restored after all. Feels like every bit of 235 bhp. Now I just have to solve an exhaust leak

 

That's good, but this usually happens to any car, once the ecu;pcm, or wtv the thing is called, its like it resets itself in order to figure everything out. lol @ exhaust leak