I have a 1998 gmc jimmy with the 4.3 having some issues when i start the truck i am only getting oil pressure and battery gauges are work ing nothing else is working the truck starts and runs fine but when i am having this problem the truck is slow moving almost like it nots shifting maybe because the speedo isn't working but if you push in the trip reset button and hold it all the gauges stay up but as soon as you let the button go they go dead i checked all harness's grounds, battery, and even put a new ecm in it and it still does it any help because if i dont get any help. i get rid of it also the key will not release out of the ignition also

 

thanks guys it was the ignition switch