Specs: 04 RX8, MT, stock, 77k miles, regular oil changes

For maybe the past month or so (possibly longer, time flies...) my car seems to hover in rpm's when shifting. The best I can relate it to is if you drive an AT and press the accelerator too far when not in range on rpms, the engine rev's up maybe 1k or so for a second, then drops to "normal" range. I thought at first maybe I was tired and shifting too low, but that doesn't seem to be it. For history, I drove a manual sunfire to 215k miles (no replacements), and now the 8 to 77k miles so far... I am sure my driving/shifting skills are fine. I replaced the coils last summer so I am ruling that out as being the first thng wrong. In addition, usually the issue with coils failing is loss of power... this issue is odd revving. Also, the engine has been rough at idle for some time now, as in it seems like it's oscillating off-center. Again, something I'm sure I've just gotten used to over time. From what I've read on here the rotaries that don't fail at 30k usually go around 70-80k, though some have been fine. I don't know if the "rpm hover" is due to lack of compression, where it takes more out of the engine to get in range for the shift (almost like starting current on a battery).

I have done a search on cat's, rpm's, etc., and haven't found anything similar to help me. Any help is appreciated... I don't buy that it's just a car getting old.

 

I may have misread your post, but to me it sounds like your clutch is on it's way out...

 

I have an automatic 8, but judging by your description, it definitely sounds like the clutch. I've had enough manual transmission vehicles to recognize that behavior.

 

I'm wondering if it may also be the engine mount brackets... it'd explain the rough idle, but per the TSB also revving hesitation. Not sure it's it, but better than a new clutch for now, especially if it's covered under warranty (I am confused on the revised TSB warranty rules though).

https://www.rx8club.com/series-i-trouble-shooting-95/violent-idle-when-ac-200719/

 

I guess the above was wishfull thinking... knowing what direction to look in, it seems you guys may be right about the clutch. Though apparently a broken mount can cause the clutch to wear. Good link below...

http://www.tpub.com/basae/93.htm
A broken motor mount (engine mount) can cause clutch slippage by allowing the engine to move, binding the clutch linkage. Under load, the engine can lift up in the engine compartment, shifting the clutch linkage and pushing on the release fork.

 

Clutches are wear items. They are like a giant brake pad in a way. 77,000 is not unusual. And yea the pass side mount likes to fail (heat prob).