I have a 1998 gmc 4x4 that code 1404 has poped up and i would like to know what it means and what to do to fix it

EGR Valve Closed pintle Position This valve is located on the intake manifold near the carb (behind I think) It looks like a flying saucer on its side with a six sided raised portion and a vacuum line going into it. If you push on the valve diaphragm (side opposite the raised portion I mentioned earlier) it should move in and out without too much effort. Be sure the engine is cold to prevent burns. If the valve is stuck - replace it. There also may be a filter in on a bracket near the valve if your vehicle is equiped with an electronic VRV (Vaccum Regulator Valve) Hope this helps. Let me know. Thanks

Code 1404 EGR pintel position closed, the test is a long one and requires a scanner, but better then 80% of the time it is either a bad EGR valve or a plugged passage under the valve.