still can't get RPM over 1500...please help.

So, I have an 88 Range Rover, 3.5.

It starts after a few cranks, idles (a little bumpy), and when I depress the accelerator, it spools up to 1200-1500 and then bogs out. To bring it back to idle, I need to feather the throttle until it is back.

I have done the following:
plugs,
wires
cap
rotor
coolant sensor
idle air by-pass motor
fuel filter
fuel pump


With all of that, the exact same thing occurs. I have researched the same symptoms, and everybody seems to fix it with the fuel pump...that was my last effort.


Can somebody please guide me. What should I do from here.

Thanks
Jason