1999 Land Rover Discovery

Engine Performance problem
1999 Land Rover Discovery V8 All Wheel Drive Automatic 152000 miles

I recently purchased a 99 disco 1 that had been sitting around for several months 'cause it needed a fuel pump. I replaced fuel pump and filter got it running to get it home but it had run badly. I have replaced crank sensor, idle control sensor, throttle positioning sensor, coil, plugs, wires, purge valve, o2 sensor [1], mass air sensor and cant seem to figure out what else could be wrong. Tested with a obd11 and has of code of misfiring. Could this be caused by a leaking manifold gasket? I am wits end and going broke trying to fix it. I have a 97 disco with the same motor that does run can I swap motors?
Robert wallace
November 11, 2009.

A leaking intake manifold can cause rough running and misfire codes. Usually with P0171 and P0174 codes?

Dave H
Nov 26, 2009.