I have a problem with fuel pressure while driving. heres what happens, when i first start the car up fp is 5psi ,just about right after i take off it goes up to 6 and stays there. If i really get on it any more that half throttle the fp goes all the way to 0 and stays there until i let off the gas then it slowly moves up to 7psi. What could be casuing this, i have a mildly built 350 with about 300hp an edelbrock 1406 and mallory fpr with return port. One more question is about my a/f gauge, at idle it reads just into the 1st rich bar when warmed up but as soon as i touch the gas i goes off the scale lean if i get on it more than half throttle ill get a reading almost rich and when im floored its pegged rich. I was told that even the slightest leak before the oxygen sensor would throw the gauge off, but does it make sense that around 60% throttle i get a reading and it seems right? I am basically positive its not lean, one reason being i get 9mpg lol. All help is aprecciated.

 

I think its the damn mallory regulator everytime I start my car the fuel pressure is different.

 

I was talking to a friend of mine yesterday who has the same regulator on his carbed mustang, he said when ever hes at wot it goes all the way down to 1psi, He said something about the springs in the regulator causing this. Anyone ever heard of this cause if this is the problem ill just go get a different regulator. All help is apreciated