i just had the fuel pump replaced. truck ran fine for 3 days. now it wont start. it cranks but it won't start.

 

wow.... theres so many different options why it wont start.. take it to a mechanic if you dont know the basic things to check...

check for spark
check over all connections
Id check the fuel inertia switch... it might have switched itself off for some reason after the fuel pump change.