I recently got into a 93 gmc sierra half ton that I knew was going to need some work. I know that there is a very good chance I will be replacing the alternator. the truck has a really decent 350 motor in it. When i get up to speed the mph guage is glitchy and "twitchy" untill you keep it at a steady speed then it kind of settles in. I also noticed the oil pressure guage and the gas gauge will go into the red untill im almost at a complete stop then they jump back up where they should be. Should I go ahead and replace all the stepper motors?

is the low alternator the cause of this or will I need to replace the entire cluster panel? any tips or ideas are apreciated.

 

Start with the alternator if you suspect it has a problem. Voltage makes electronics do some weird things.

 

i get the same thing with the ammeter in my truck, my needle shoots up to full when i get a weird noise from my alternetor, as soon as the noise stops the needle goes back to where it should be.
i was told it could be the alternator or i might have a short in the wiring causing the alternator to react this way.
i broke down last week and had to replace the coil and module in my distributor, wouldn`t be suprised if this was linked to the problem.