Hey all! I posted this questions in the dumb questions thread and didn't get any responses there so I'm asking here. If this isn't the correct thread I apologize, let me know ill move/ delete it.

I'm trying to figure out a issue I'm having with my 2005 Rx8. When I'm in gear the rpm's keep bouncing between 1.5K and 1K in a almost rhythmic pattern, and it only does this when I'm in gear and the clutch pressed in. When its in neutral the idle is just fine without issue, and when I give it gas it runs fine as well, the RPM's only move around if it's gear and the clutch is pushed in.

There's no CEL for this issue(not yet anyway) I tried searching for a answer and I'm having a hard time finding it, my research states it seems it could be either the clutch pedal position switch or a bad neutral switch or something else, but tbh i have no clue.

Any advice would be greatly appreciated

 

Sounds like clutch pedal is out of adjustment and the clutch isn't fully disengaging. The pedal has an adjustment screw, you need to raise the engagement point a little.

A quick way to confirm this: on level ground hold clutch in and put it in 1st. Does the car creep forward?

 

Sounds like the clutch safety switch needs to be replaced.

 

Hey! sorry for the late response but the car doesn't creep forward at all. odd thing is, if i give it a tiny bit of gas its fine, no bouncing. in neutral its fine, doing nothing with clutch fully depressed, it moves.

I hope that's the case. researching that part looks fairly cheap. i just had my clutch replaced a month or 2 ago and that costed me a pretty penny. Think that could be related in any way?

Also ,i have a video of the issue. Please ignore my childish sense of humor.

 

Good News everyone!

Turns out Mr_Insulin was correct, it took forever but my car finally through a CEL, P0704, bad clutch switch!

Thanks for the advice!

 

I'm having the same thing going on but I have no idea where the switch is. Recently my safety switch went bad and my friend I bought the car from just hard wired it and now I don't have to press the clutch in to start it up. Not sure if that has anything to do with it though.

 

I'm not much of a mechanic so take my advice with a grain of salt(i was asking for help here to begin with!), but it seems like this should be it (the item circled in red).