1994 Chevy Suburban timing problem

NOTE: Timing specifications are listed on the Vehicle Emissions Control Information label under the hood. Always follow the Vehicle Emissions Control Information label procedures first before using the following procedure.

Timing Mark

PROCEDURE:
Set timing under the following conditions:

* Normal operating temperature.
* Air cleaner installed.
* A/C "OFF."
* Transmission in neutral.
* Disconnect SET TIMING connector. The location of the set timing connector is inside the cab where the heater box and the carpet meet on the passenger side floor. Pull carpet back to expose the single wire and connectors on the outside of the control module harness. The wire colors are tan with a black stripe. DO NOT disconnect 4 wire connector at distributor.

Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor. For specification, refer to SPECIFICATIONS/TIMING MARKS. Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear control module trouble code by disconnecting control module power source. With engine at operating temperature, drive vehicle at part throttle with moderate acceleration and decelerate to idle condition. This will "teach" the control module and return the engine to normal performance.

This is what we did and they didn't give me the option to put the motor type 454 7.4 liter

Sorry was not trying to disrespect. The purpose of the copy/paste was to share what we were reading. There can be changes that maybe we were not aware of. We did disconnect it each time we tried to set it. I am pretty sure it is a timing chain issue as I am a former Chevrolet technician but after trying the things we have I needed to pacify my mother who's vehicle it is. Thank you for your time.