i recently got into a truck i plan on fixing up a bit. its a 94 gmc sierra half ton 4x4. when i get up to speed the mph guage is jumpy and twitchy for awhile untill you keep a steady speed. Also the gas gauge and oil pressure gauge are completly in the red untill you stop or slow down and then they jump back up. Could the alternator being low cause this issue or would i have to replace the whole cluster panel i believe its called.

you can get the alternator tested for free at autozone.

could be the voltage regulator or it could be a cluster problem.

Those trucks are known for the clusters going out. I had a 96 with the same problem. first the oil pressure got twitchy, then the gas gauge quit working. I replaced the clusted for 60 bucks and it fixed it. good luck to you.