| While I don't think 3000 rpm will kill it, that is higher than spec. A lot of people adjust the max governed speed up to 3000 to get some more road speed. You can adjust this down usually by the high idle adjustment. I haven't looked very close to these injection pumps but usually on one side of the control lever will be your slow idle adjustment and on the other end will be the high idle. The high idle adjustment stop usually has a tamper evident safety wire on it so repair facilities would know you had upped the max rpm. If there's nothing on it then whoever had the truck before you likely adjusted it up themselves. There are some pics on this adjustment on the net somewhere but I don't recall where. | 
