car is getting spark but cranks with no start on 2003 Buick Rendezvous

already replaced crank sensor and spark plugs

Fuel pump!
1 more answer
Many things can cause this condition.
- Fuel pump
- Fuel injectors
- Ignition Control Module

You need to see if it is getting spark and fuel pressure. If these both check OK, then I would suspect the ignition system (coil packs, ICM, or crank sensor).