intermitant starting cerb 4.5

[cerb ian]

some times i can start her straght away but other times i go to start it and no fuel pump primes so i bypassed the imobilizer an the problem is still there but only say 1 in 40 times it wont go also thought it could be the f pump relay so put a new one on and still the intermitant problem is still there any pointers ????

[Tanguero]

Poor connection in the starter solenoid circuit sapping voltage to the solenoid perhaps?