Sometimes I turn the key, solinoids start clicking away and no starter

. Pop bonnet wiggle starter wires, it fires up. Samething same day, wiggle starter wires, nothing, try fuseable links on drivers side, it fires

. Mate took wagon, nothing, when he got back he showed me what he did I couldn't beleive it... he wiggled the throttle position sensor wires

(he's not mechalical).
So can someone tell me whats going on?
Cheers Paul