Ok, this is going to be an interesting diagnosis I think... I've transplanted the engine into a Polaris RZR, it runs great ...up to about 9000 RPM's in first gear and about 7000 in other gears. I haven't been able to drive it a whole lot, you can tell it wants to accelerate but it just won't. I don't believe it is a spark issue, and I believe that it is getting enough fuel, I am dumbfounded. It is NOT throwing any codes (I unplugged the vac line to the MAP sensor and it did throw a code, so it is capable of throwing them)... I have an aftermarket fuel pump and regulator, I have set the fuel pressure at 45 to 55 lbs to see if anything would change, it didn't change when I changed the fuel pressure, and the pressure stayed constant while I was driving it, nor did it didn't change when I changed the fuel filter (pre-regulator, so it shouldn't matter, but I did just so that I could rule it out). I have also changed out the coils, it acted the exact same. I'm not sure if it's rich or lean when it falls on its face, we don't have any dyno's around to wideband it. Any ideas?