I posted about 2 months ago about my 4.9 E250 with 140,000 miles that has a stumble and buck when accelerating. I have replaced the throttle body gasket, numerous sensors, cleaned the PVC and EGR, and gotten the codes to go away but the problems remains UNLESS I hold the keyswitch just past run into the start position when the ABS light comes on. If I push the keyswitch a little further the radio and wipers stop working so I have found this "sweetspot" where the turn signals, fan, speedo, do not work, but the van does not buck and runs fine. It's a pain to do this but less of a pain than driving a bucking van. I also discovered that the van runs perfect for the first 1 to 2 minutes right after it is started and is cold without having to hold the keyswitch past run. When I hold the keyswitch past run a can hear a relay either pull in or drop out somewhere near the left front firewall in the dash. I'm sick of this issue. I'm thinking that holding the keyswitch is simulating a cold start and maybe richening up the mixture or something like that. Any thoughts?