Researched these codes...

P0076 VDI solenoid valve control circuit low

and

P2259 AIR solenoid valve control circuit low

I found pictures to locate the AIR Solenoid; but haven't been so lucky with finding help locating the VDI Solenoid.

Would fault with either of these explain a sort of knocking/clanking sound when accelerating? The sound mostly happens when accelerating aggressively, and doesn't happen all of the time, usually persists at around 3-5K RPM and then stops.

I took it to the dealership and, if I remember correctly, the service guy told me there was "Carbon" build up on some-part-or-other, but it confuses me how there would be carbon build up on intake parts. I don't want to get raped by dealership prices if this is a relatively easy fix... according to them I have about $1,500 worth of work that "needs" to be done. F that.

Also, I have an automatic tranny... recently my car has begun to sputter-out and die at idle, sometimes it won't start unless I work the gas peddle.

Any help is much appreciated, I have tomorrow off so I'm planning on taking the intake manifold off and getting a good look at the AIR Solenoid and checking it's condition.

For anyone else with AIR Solenoid problems, this thread is/was very helpful:

https://www.rx8club.com/series-i-trouble-shooting-95/p2259-locating-air-solenoid-171612/

 

All of both of those solenoids (along with the SSV) are on the back side of the intake manifold. It takes a bit of work getting to them to get them out and test them. Keep in mind that testing good doesn't mean they are good, the test really is only good for seeing if they are really bad.

As for the knocking I'm not sure.