Yeah this is a tricky one. Will be a learning moment when we figure it out. To be fair, nobody anywhere drives rotaries You're lucky to be next to Racing Beat, could be a resource of expertise or parts. I'm not even sure how they survive.

 

YEAH, I think most of their sales are with Miata parts lol.
I found a thread almost identical to mine but of course no end result. I find a lot of threads here on this website where people don't come back and tell what the fix was. Very frustrating.
Heres the link https://www.rx8club.com/new-member-f...ed-afr-266686/
I was also thinking it may be due to the Racing Beat flash tune. Before I had the porting done I had the REv 1 tune, now after the rebuild and streetport I had the REV 3 flash tune installed. Ever since then I have been having these issues but its hard to say because I had the engine all apart and made many changes. But one thing that I find is that at WOT it doesn't seem like the ECU is making changes for lean condition. Command lambda seems to be stuck at .988-1.0lambda. If the ECU sees lean condition at WOT then why isn't it adding fuel? Unless RB software is designed to run that lean? I doubt it as they are pretty conservative.

 

Update, still waiting on airmass sensor and o2 sensor to arrive. The guy who was supposed to order it dropped the ball..... SMH. Anyways, my son has driven it for 600 miles now and its still doing the same idle thing but the check engine light just came on today for p0507. High idle, I assume from the idle issue, however the lean code did not come back. And whats really interesting is we removed the cat over two weeks ago and no check engine light is coming on for that. The first time I deleted the cat a long time ago the check engine light came on right away for obvious reasons

 

Still waiting on parts- long story- anyways changed oil after almost 1000 miles of driving after rebuild. Oil looked good, no metal. Pulled leading plugs for inspection and plugs actually look like engine is running Rich, not lean. Which makes me believe there is a bad sensor- airmass or front o2.
Pic of plugs

 

Finally got airmass sensor and installed it and it’s doing the same thing. I’m going to have my ECU re flashed again from Racing Beat and go from there. Short term at idle is still+ 16 and airmass is 5.6 so I don’t get it. Makes zero sense why it’s doing it when all the values look ok.

 

1,280 views and no one has had this issue??????

 

Have you checked the purge solenoid on the upper intake? You did a smoke test for vac leaks? If you didnt have any smoke appear while the engine was off, perhaps it is on something that turns on and off while at idle.

Before spending more money on random components, I would do another smoke test pre and post throttlebody. Afterwards I would double check the injector wiring again and your ignition coil wiring>sparkleads. Replacing the front O2 may be wise, as it could have been damaged when you swapped headers.

If your hot compression is 110 @250rpm that is pretty great.

 

I already smoked it and sprayed everything down with carb cleaner to check for leaks. No leaks found anywhere. Replaced fuel injectors, double checked wiring- all good. Coils, plugs and wires are all brand new. Purge valve is brand new and no cracks or leaks found in lower, upper intake or accordian. Fuel pressure is steady at 59psi.
Engine runs great at regular speeds and wide open throttle. Its only the idle circuit that I have an issue. When you start the car it will idle like a bridgeport and then smooth out. Once you blip the throttle the idle will go down to around 500rpms and then almost stall and then the ECU will add fuel +16 to bring idle back up to 800rpm and then the idle is fine until you blip the throttle or while driving and put the car in neutral to coast to a stop it will do the same thing. The only thing thats weird is the spark plugs look like its running rich, no lean as seen in the pic I posted. So maybe the front O2 sensor is reading incorrectly giving false input to ECU and the ECU is correcting it. It's almost as if the ECU is not adding fuel correctly during decel RPM below 1000rpm.

 

Have you checked TPS and the throttle body itself? Is there a way to swap to a different one for testing?

 

I cleaned the carbon build up on throttle body and blade. Checking all I did was check actual values with my scanner to see the percentage when pressing the gas pedal and it seems to be reacting ok. Like I said, it only acts up when throttle is let of and rpms drop back down to idle and on start ups. All other acceleration is normal so I wouldn't think the throttle body would be bad but it may. Normally when things like that dont jive it throws a code. I have no codes for the last two weeks but sometimes get a code for running too lean at idle and high idle circuit but those codes have not returned. I even have the catalytic converter off and I get no codes for rear o2 sensor which is very odd.But I'm not complaining about that lol

 

have you found the issue yet i am having a similar and would love to know what the issue is

 

Not yet, I replace the airmass sensor and its still doing the same thing. I'm going to take the ECU back to Racing Beat and have them re due the flash tune as I think that may be the issue, and then if that doesn't fix it then I'm going to replace the front O2 sensor

 

Update...... havent had time to replace anything. Engine is running ok but still get the idle drop coming off acceleration. The check engine light comes on about once a month or so for high idle or engine running lean. When you start it up it will idle like a bridgeport for about 8 seconds then smooths out. This got me thinking. When I rebuilt the engine I was very careful marking things but I'm thinking what if I put the front rotor in the back and the back in the front? I know there is scallops on the leading edge of the rotors to help with timing. I'm wondering if maybe someway i mixed them up and the scallops are on the exhaust side now causing exhaust ovelap and thus my bridgeport idle and overall idle issues. Has anyone every mixed up the front to back rotors and if so what did it cause??????