I have a Clark C30L, and usually it runs as it should, but about once a week or so once you start it up it just stays in idle and you can't go either direction or even rev it up. Once you shut it off and start it again it runs fine. The operators are getting annoyed of it so i'm trying to locate what could be causing it.

The truck also has a check engine warning on the display, but i'm guessing i don't have the software to locate what is bringing that error up.