In the last month I've started noticing a problem with my '04 MT RX-8. If I start the car when its cold (regularly 30-40 F here recently) and I lay into the gas the RPMs reach 5500 and then it falters, struggling like it wants to go higher but just can't. Always the same point: 5500 RPM. If I let the car run for another couple minutes it goes away, but I'm still bothered by it. Right now its running on 5W20 Mobil One synthetic oil. Any diagnoses? Dying secondary injectors?

its the ECU protecting the engine. do not do that. just let the ECU do its own engine warm up process. trust me. at the low winter temps, you dont want to be pushing your engine like that.

At what stage in the warm up process is the rev cutoff eliminated?

OMFG I JUST WITNESSED THIS SAME PROBLEM AND WAS ABOUT TO POST A NEW THREAD LOL...

anyway...i was driving a lil while ago cruisin in 4th at about 40mph...trafic picked up so i down shifted to 3rd so i can accelerate a lil faster to catch the light....the engine felt like it fell flat on its face i was at like 7k rpms in 3rd trying to accelerate but the engine slowly went down back to like 4k as the car slowed down. i tried again to push the pedal and it will rev up to like 6k then wont go past that...as if there is fuel cut off....but heres the trick...i know the fuel isnt being cut because the car shoots flames like no buddies business as i push the pedal...if i go 3/4 throttle i hear rapid shots and can see the flashing of the exhaust flames....so if i had to guess id say its ignition related but i dont wana start ripping stuff out if im not right. i figured the car was maybe tired since i been drving all day so ill try again tomorow. btw im in S.FL and its like 69 degrees so i know thats not the problem...any ideas????

Try reading your owner's manual.

what happened to your sig MM? it looks like a ghost

Try reading your owner's manual.

On 5-4 in the 2004 OM it states that fuel supply will be cut at a lower rpm than redline when coolant temperatures are "low". MM, do you know what range the computer considers "low"?

I knew that the cut was there, but I don't plan to testing it to see when it goes away ;)

anything below 162°F.

I get the same exact thing except it only happens when she is really warmed up. Other determining factor is AC on.I never get her past 4k until she is warm, then she runs good for a long time until she is hot, and sputters around 5k. Also, I can be in 5th gear at 72mph and stomp it and she does not go anywhere. Totally different with the AC off.

Is this something I have to live with? Here in FL, it's damn hot 6 months out of the year.

Ack people! You cannot beat on the motor while it's still cold. The motor is made of different types of metal which expand at different rates. Racing the motor while it's cold could result in serious damage which is why the PCM prevents you from exceeding serious RPM's.

As MM said, read the manual...I hope you guys check your oil level too!