My car is making some odd-ball sounds from what seems to be coming from the "Air Control Valve?" on the passenger side of the engine bay, down low. It makes a wierd popping sound that is intermittent (sometimes most prominent at warm-up and sometimes at speed on the freeway). It doesn't feel like it is cutting the engine out but it "sounds" like it's missing - the engine firing that is

Does anyone know what a failing Air Control Valve sounds like? ....and does anyone know how much those things cost if they do?

Thanks!

 

I can't explain the sounds, but I had the "missing" problem you refer to on my 7. I removed the AVC and it cured the problem. My last rotary (84 Cosmo) also had the same problem and the same cure. I think these quite often fail with age.
Do a search on how to do this, there's lots of info here.

 

NZConvert - You removed the ACV?

I live in Southern California and still have to pass smog. Doesn't that cause a problem with that?

 

Yes. Removing the ACV removes airflow of the air pump to the cat. The air pump becomes useless, unless you hook it up another way. You will not pass if you block it off.
You probably need the a new check valve, they tend to eat themselves and then flow both ways.
Sean Cathcart.

 

Yep, you'll need to keep the air pump, AVC and cat. Sorry to steer you wrong, I didn't know you lived in CA.
Do you need to pass a visual inspection? Do they check everything is still in place? I've heard of guys on the forum ditching the ACV, piping air direct from the air pump to the cat and passing emissions tests, but CA's required pass levels might be lower.
Otherwise you'll just have to get a new ($$$) or s/h ACV.