Yeah, bump on this. Stray away from adjustable FPR's, FMU's, ect. You're simply going to be temporarily avoiding a problem (as SUV said, it's a BANDAID!). Sooner or later it will pop up again.
Find a set of injectors that are sized well for your application and get it tuned. Getting more fuel into the cylinders is only part of the problem. There is also alot to deal with when it comes to the timing and load calculations, etc. in the computer. The amount of air a stock 4.0 pulls at full-throttle could very well be what you will flow now at say, half throttle, and the computer can only compensate for this difference so much. Inevitably, an FPR will get you by for a while, but your driveability, fuel mileage, and longevity of everything will benefit greatly from doing it right. The initial investment is more, yes, but it's worth it.
