Definitely look at the ground cable , make sure its not corroded where it meets the frame ,opposite end to where the ground meets the battery. Check the ground on the fuse panel next to the battery and also reseat the ECM and the PCM they're located next to the battery . Ones below and in front of the battery and the other is on the end of the engine compartment fuse panel. Check that there's no corrosion in these connectors and use dielectric gel when reconnecting to keep the connection clean and dry. Make sure they are locked in when done. Hope this helps