id agree with the fuel pressure reg. i had issues with my vx where id accelerate fine but then as i hit 3500-4000 rpms i would get what could only be described as a hiccup, where the engine felt like it was frozen at that rpm for a second then wouold take off again as normal, fuel pressure regulator greatly helped that problem

y33.. be careful.. i did a similar thing with waiting and guess i bounced the fpr around a little too much because as soon as i installed the new one i was running rich.. so had to replace it AGAIN.. and now all is well