Hello Everyone with this problem. I have been through the sh#t trying to figure out stuttering and spitting at about 7,8,9000 rpms. I did everything from fuel pressure flow test, adjusted timing and valve clearances, new plugs, checked coils pulled out and cleaned injectors checked for vacuum leaks changed oil. Replaced iat sensor replaced Iap sensor changed tps and stps to checking wiring all with no codes showing at all. So I was stumpped and could not find answers anywhere. So what I have come up with with trial and error and testing is I believe the problem is stva even though it test fine. I have them separated at the connector and have been testing I had to enable the accelerator function on my PCV and make adjustments to settings and test make more adjustments and retest I am still fine tuning the accelerator pump function but it's just about there. Some people would call it the day or done deal the way its running now but I believe I can get her to run a little better. I ordered the heal tech stva eliminator to cure the fI light and code. Yes it shows a code when disconnected but not while it's connected go figure. But if I get this fine tuning to where I'm satisfied I think I will just eliminate the secondaries permanently. Ebay sellers want $250.00 and up just for the stv actuator. I'm on a fixed income that's alot of cash for me just for that part. I don't know pros and cons to secondaries being deleted but I'm running better than I was. I could not even do a power up wheelie and I run a 08 1000. Buy she will yank the front up once again. This might not fix your problem but if you tried all the standard diagnostics check with no outcome this might be the next thing to check. If any one knows about the proper way to work with the PCV accelerator pump settings it might save me sometime. Not much info on Dyno jet web site. Also could use some input on pros and cons running with out secondaries. Hope this helps someone that is as frustrated as I was. Ride hard but keep y safe.