1997 GMC C1500 tart trouble

The starter is it cranking the engine over or it cranks over and refuses to start

Check the fuel pressure with a fuel pressure gauge designed for your fuel system-if okay-check if the injector/s are pulsing meaning its opening and closing-by listening for clicking noise or you can use a noid light to check

Now
coudl a faulty starer alter the truck's timming because
it shakes buyt not starts.

The starter's job is to crank the engine over that's all its got nothing to do with the car shaking

Now can the engine's timming can be
moved by mistakeinly move the distributor: You cannot move the distributor mistakenly-you have to loosen the holddown bolt/s for it to be out of time.

Do below to determine if its fuel or spark problem

Disconnect a sparkplug wire or 2 and ground it to the engine -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, distributor pick-up coil, ignition control module, cam and crank sensors- Note: If it doesn't apply disregard it