I've been trying to dig through the forums and I haven't found it yet and I'm just curious about this. My RX-8 when I start it, will rise to 2000 RPMs and then fall to 1000 RPMs. It will go back up to 2k and back down to 1k. Almost like I'm tapping the Gas. It's almost a rough idle when it drops to 1k and then jumps back up to 2k. Even sounds like it's trying to stall itself lol but It does this for about 4 to 5 mins before the temp gauge starts moving and then it stays idle at about 800 RPMs. I'm wondering where I would start on an issue like this before going down a rabbit path that may not even solve the issue. Fuel Pump was just changed (It did this before the fuel pump was changed.) along with fresh plugs and oil. So I'm curious if anyone else has ran into this issue? Any help is much appreciated, or maybe a guidance to a thread that may go over this issue. I don't expect anyone to fully tell me as no one is here to hear it but any guidance to the right thread may help the most.

Thank you in advance!

 

try cleaning the maf and ess then do the 20 brake stomp and see if anything changes

 

Noted I will give that a shot! That seems fairly in expensive and a good quick trial option!

 

be sure to only use mass air flow cleaner and dont damage it.

 

Will do! I've had to do the same thing to my 96 Maxima for a different issue so I think I still have some MAF Sensor cleaner somewhere

 

Is the check engine light lit and if so, what are the codes?
200's tips are good, and you could also look into vacuum leaks. If the intake is not stock, and poor quality, that could be another reason.

 

My 05 will sometimes start that crap, surging up and down until it gets a bit of heat going in the engine. Notice more in cooler temps but no codes, no lights, no idea.
I just drive the darn thing and keep eyes on coolant and oil levels.