I Have A 99 Chevy Tahoe That Won't Start. It Is Firing. It Has Injector Pulse Fuel Pressure Of 60lbs And Engine Compression Of 140-150lbs. But It Still Won't Start. It Cranks OK . Please Can You Help?

The truck cranks OK but will never actually start. I've checked the important sensors (crank, cam in distributor) they are working fine, while cranking you can hear like backfiring in the throttle distributor is in place all power and grounds seem OK, while cranking it seems it doesn't pick up a good rpm signal in dashboard the rpm gauge doesn't move at all.