Vehicle is a 1994 Nissan D21 Hardbody or pickup. 4 cylinder, 5 speed, 4x4, 94,000 miles. There is no issue when the ambient temp is warm or during spring or summer or early fall. When it's cold and I mean cold as in the problem only occurs when it's 45 degrees or below and the vehicle has been sitting for a couple hours, it won't even turn over. I hear a very slight click and it is the fuel pump relay. Even when cold out if I turn it off after completely driven a nd warmed up, it'll start right up. When I'm lucky, if I hold the key turned over and wait sometimes it will eventually go click......click....click..click, some rapid clicks then turn over till it fires up. If it turns over it starts without fail, the problem is getting it to turn over. I've replaced the starter 2 times, the starter relay and have used OEM on everything. PLEASE HELP!!