shop gave me a service bulletin about distributor bushing and the attached scans. put new ignition module in distributor and had no fire condition. put old module in and started right up. now leaning to a faulty distributor.
shop rebuilt 4L80E for my K3500. However, over 60mph the tcc locks and unlocks. shop said its external to trans. there scan points to erratic rpm. distributor seems snug and replaced tps. truck still in and out of lock up over 60mph. any thoughts?