Rough Start
 

Yes, I've searched...

I still have the 04 6mt w/ 95k on it (getting up there) daily driver.
Removed the failed cat @ 40K
Replaced coils and sparks about 10k ago
Also replaced the fuelpump at this time
Replaced weak starter @ 75k

Recently I've noticed once it starts from sitting overnight it will miss and idol rough for the first 5-10 seconds after starting... my fear is that coolant might be leaking and the rough idol is from the coolant burning and clearing.. There's no external leaks (puddles, etc) and I have a faulty coolant senor (I disconnected rather than replacing) so that's no help... If it is coolant, it's not major enough to tell from the reservoir..

Has anyone has a similar issue?

Does it start up straight away? Does it drive well when warm? Do you have any power loss?

If your coils, plugs and wires are ok and the car drives well with all its power, I would suggest resetting the ECU and see if that helps.

Need more info from you so I can help if I can.

Pull a sample of your oil and send it off for testing. Does your car smoke at all when yu first start it(from the exhaust)? If white smoke comes out of your exhaust then you might have a coolant seal out. Have you check your coolant or monitored you engine temp out all?

He said it's not enough to notice from the coolant bottle, so I doubt it has anything to do with coolant seals. It could be as simple as a dirty air filter and MAF. Also the throttle body could need a clean also. We always have the bad habit as RX8 owners to jump to the worst case scenario of compression and engine problems. Most of the time it is something simple.