Good Morning. I'm a long time user, first time poster. Been searching but haven't found previous posts that address my issue. I have a 1999 7.3 4X4 Crew Cab Long Bed 4R100 trans, 350,000 miles. At idle, the RPMs drop to about 500. Feels like the torque converter is trying to lock up. The idle then jumps back up to 800 or so, back down to 500 and so on until acceleration. Does it in drive and reverse, not in park. Sometimes, the shift from 1st to second is a hard bang. Transmission rebuilt 3 months ago. Had Code P1746 after rebuild, transmission shop warrantied the coil pack but symptoms are the same. Thank you for any advice and help.