Fuel pump?

[draggin75]

I have a rather unmolested 89 240SX with the exception of buying a junkyard engine and running 2.75 exhaust with a flowmaster and a stainless muffler tip its never been touched. The thing is, is that the engine I bought has GOT to have been rebuilt because it looks like its been into and it runs like Godzilla's chasin it! The question I have is that when I run it up to 3800rpm it just shuts off like I turned the key off...... all the electrical is still working the whole time and when the rpms get down to 3300 it starts running again! It ALWAYS shuts off at the same rpms and starts back up at the same rpms. I'm pretty convinced its the fuel pump but wanted to make sure. Also, off the line it runs up to 5000 rpms or more without shutting off.... its when its a slow steady rise in rpms is when it seems to do it the most. Thanks for any and all help!

[elwesso]

if its a fuel presure problem that should be easy to find. Get a fuel pressure gauge, T it after the fuel filter and then run enough hose to have the gauge up in the cabin... If it drops off then youll konw you have a problem.