Hey guys! My Rx8 has been running super exceptionally since I had the engine replaced with a rebuild and a new clutch and exhaust. However, its now been 7 months of driving fine and now the idle is all screwy. As I drive, the car surges, and when I stop at a light, the RPMs consistently move between 750 and 3k RPMs, and at times it shuts off on idle.

I took it to the Mazda dealer and they said that it may be the throttle body, but they did a function check and reset something and it was supposed to work. I got the car back and after 20 minutes, it did the same thing. They told me to park the car, turn the key to acc and pump the brake until I see the oil pressure build up and then turn it back on. I did this multiple times, and nothing has fixed it. So I guess I have to go back and get a new throttle body. Mazda quoted me at like $800.00.

Any ideas, comments, or suggestions.

-digitalmonkey79

 

It could be, but TB failures are pretty rare. Maybe a local member could help you out and let you install theirs?

 

i have a spare if ya need one

 

I'm not sure what in the TB would cause that behavior... there are plenty of moving parts, but they don't really fail in a way that makes your idle flop around sometimes.
I'm more thinking a gasket in the intake is leaking vacuum or you have a loose vacuum line. Definitely cheaper than $800 to check first?

 

Yeah, that makes more sense to me as well. I'll definitely check out the intake and hoses in that area. Thanks for the input.

 

Neutral switch is the problem.

Can't find thread now, here is one that had different problem.

https://www.rx8club.com/series-ii-te...switch-256826/