My 2004 chevy silverado duramax speedamoter is not working right, sometimes it don't move other times it goes to 120mph

There was a recall on this problem

I had that problem on my 01 Sierra, Lithia said it was the ignition switch, 500 dollars later it wasnt the ignition switch. I traced my problem to a loose wire on the main fuse box under the hood. It connected only sometimes which caused my guages to snap around. Hope this helps.