Hi people wondering if anyone can help,my pride and joy keeps dying on me,can be driving along the out of the blue she just dies like the ignition has been cut,if im travelling at speed

then i can usually re start or it bump starts itself but if im dropping speed or slowing or just about anywhere i have to pull over and it wont start,if i wait a few mins it fires up great again.
Ive just changed all leads,plugs,rotor arm,d/cap,cam belt new exhaust but still does it???
someone said to change the fuel pump relay? is this right? also where abouts is it on the car,in the fuse box? cheers people