88 gta 350 once in a while these 3 guages, have double lines, does anyone know y they are like this.

 

They are probably going out. Wish I had better news, but those digital clusters either work or they don't. Yours is probably becoming one that don't.

 

thats right mine did the same thing but it was after transmission upgrade and eventually crashed. Searched around and had new wiring harness made and changed a bunch of other crap. Another buddy of mine had same problem but he had recently contacted a company called painless and have not heard back on how he made out.