I have owned my car for almost a month now and i 've been having a problem with giving the car full throttle. It keeps getting stuck between 4500rpm & 5000rpm. At first i thought it was the transmission but then it cut out between the same RPM while it was in nutrel. So my cousin suggest i was not getting enough fuel, so tonite we un-hooked the vacum line on the fuel pressure regulator and the car drove the same...shouldent unhooking that line affect the cars performance? Also the car starts backfiring once it hits the problem spot in every gear. It shift fine at 1/4 and 1/2 throttle but as soon as you stomp the gas it cuts out at the above mentioned RPM. It has totally robbed all of my performance.. I need help, thanks guys.

 

the only way to be sure of your fuel pressure is by using a gauge. it should remain relatively constant at 43.5psi stock.
jesse

 

You might want to replace or check your fuel filter, plugs and wires.