OK, here is the situation. I have had a stumbling problem on my engine ever since I had HKS 272 cams installed. At low speeds of 1400 to 1500 rpm, my engine stumbles, hiccups, hesitates, whatever you want to call it and then picks up as normal after such point. I don't know what could be causing the problem.

I recently had my car tuned by Dr. Gray (thank you) with the SAFC, 660 injectors and the other requisites mods. As far as BOV, I have tried the Greddy Type S and the JDM MR valve and the car will stumble at exactly the same point for either BOV. The car makes awesome power, but the bogging at low rpm is really bothering me so any advice?

 

i had the same problem. mine was a tuning issue. i recorded an extremely rich spot in that rpm range and had to lean it out. now i don't have the problem anymore.

 

That is interesting. I will check that out, but I had this stumbiling problem even before installing the 660 injectors.