Low Battery Amperage

• Car batteries don't typically fail outright; they sort of fade away to the point that they become useless. As a battery gets old, its lead plates thin and degrade, which reduces the amount of amperage that can pass from one to the other. Cold engines are harder to start than engines already at optimal operating temperature, and your battery may not provide enough amperage to run both the starter and the ignition system. Take your battery to any chain auto parts store and have them check the battery's output under load.
  
  

Bad Fuel Pump

• Older fuel pumps are more sensitive to voltage changes than newer ones, and may not provide adequate pressure when starting. When you start the truck, most of its current and voltage go to the starter, depriving other systems of the power that they need. This is especially true for vehicles like the 2001 F-series, where fuel pump output pressure varies directly in proportion to voltage. The problem may be low battery charge, but the solution is to buy a new fuel pump and pump regulator. Bear in mind alsol that a clogged fuel filter can manifest similar symptoms.
  
  

Bad Ground

• The starter is your truck's most energy-hungry appliance, and places more load on the system than most other accessories put together. A solid connection between the starter power terminal and the battery is only half of the equation; your truck needs an equally strong ground cable to complete the circuit. Old, frayed and loose ground cables will create a restriction in circuit; add in the demands of an ignition system and fuel pump and you create a situation in which the truck may run fine most of the time yet prove very difficult to start.
  
  

Excess Air

• The Mod motor's computer can compensate for a certain amount of excess air under running conditions, but it might not prove as adept when the engine is cold. Engines have choke plates because they need a richer fuel mixture to start when cold; vacuum leaks, a maladjusted throttle or throttle position sensor or stuck-open idle air control valve will introduce more air than the engine needs or the computer can compensate for under idle conditions when cold. Additionally, a bad temperature sensor will trick the computer into thinking the engine is warm, so make sure that's working.