Brake Issue

[smpoulin1]

Need a bit of help, my front brakes get "grabby" and very sensitive after driving in stop and go traffic and sometimes my rear brakes act like the emergency brake has been set after parked for a while. If you set the e brake and release, the truck will roll as it should. I have checked the rear shoe adjustment several times and they are not over tight, I have also checked the e brake cable tension and it is loose when not set. I have replaced the master cylinder, the proportioning valve, all 3 rubber lines, blown all hard lines out/checked for obstructions, the pads/shoes, both front calipers and pads, and both rear cylinders and shoes. Only item I haven't replaced is the power brake booster. Any ideas where to look next?

Thanks in advance.