Engine "stumbling" or hesitation when lifting OFF the throttle during WOT runs
 

Relevant stats:

2004 GT Manual
~65k miles - original engine
Premix w/ Idemitsu or Protek-R (whatever I happen to have onhand)
BHR Midpipe (thanks RIWWP!) and Ignition w/ MSD wires
AEM CAI
Plugs have ~200 miles on them (just changed them this weekend)
Oil catch can (installed this weekend)
AP w/ MM Tune
No CEL's


Ok, so this issue started on my way home from staying at my parents house for the holiday weekend. While I was there, I planned on changing my plugs. As I was jacking up the car to pull the left front wheel, I noticed I was leaking oil :SHOCKED:

Turns out it was actually leaking out of the AEM filter on my CAI...:cussing:

Pulled my whole intake apart and it was coated in oil along with the MAF. little puddles an all.. how my car was driving well at all is beyond me.

So I clean every part of the intake as well as the throttle body and re-assemble it. I remembered I had an oil catch-can that I never installed so I put that in inline with the oil filler neck. Its NOT vented to atmosphere.

Now, you're probably thinking that my oil was overfilled but it most definitely was not. Regardless, the catch can is in so I can't see that happening again.

So, I went ahead and changed the plugs (one at a time so it's not possible to mix them up, i always do it this way) and took it for a drive. What happens is I'll go WOT in say third gear and lift off the throttle completely or even partially up around ~7000RPM and I'll experience the same type of feeling back when my cat was failing and it wouldn't rev past ~6500RPM. The kicker is, it does accelerate fine, nice and smooth. Its only when I lift off that this occurs.

Of course, there is no CEL to help me track it down.

Next thing on my list to replace is the fuel pump. Its a good thing to replace anyway, but do these symptoms fit the bill for a failing pump? I'm not sure. Anyway, if you have any ideas i'm all ears. Thanks guys!

clean SSV

Damn, that completely slipped my mind. And it makes perfect sense, too. All that oil getting in through the intake probably gummed it up.

Well, I know what i'm doing this weekend! UIM is coming off. Yes I know you don't have to but why not? I can clean it really well.

Now I'm back to being confused. I am able to freely move the SSV actuator and it snaps back into place easily. I also watched it cycle on its own when shutting down my car (i positioned my phone to take a video :yelrotflm )

Hmm. I ran out of MAF and electrical contact cleaner over the weekend but I suppose I'll pull the MAF again and ensure its clean. Other than that I'm at a loss. :scratchhe

I suppose I'll just use this to document my own troubleshooting ;)

Well, my commute this morning went perfectly fine... Odd. The engine felt great all through the rev-band. Maybe the SSV was just caught up and me cycling it manually last night free'd it up? I may just pull it out anyway this weekend as its never been cleaned.

Rickeo,

IS the SSV hard to pull and clean?
Also same questions for throttle body?

I am a gas turbine engineer and readily design blades and such for these - but the wankel scares me lol, any pointers / guide would be great/

Best regards

Quite a few thread about the subject already. Here is one for starters that comes up when you search:

https://www.rx8club.com/do-yourself-...-video-184663/