Is there a screen in the gas line on 1998 Chevy truck?
No, there's no screen filter in the fuel line itself on a 1998 Chevy truck (or most fuel-injected vehicles for that matter). The filtering is done at the fuel tank's fuel pump assembly. The fuel pump assembly contains a sock-type filter that removes larger debris before the fuel reaches the pump. There are also fuel filters located elsewhere in the fuel system, typically before the fuel injectors.