Guys, Help! My stock 53 3600 normally runs fine, but yesterday I had to have it towed home. Some history, recently addded 3 ozs. of Lucas fuel cleaner. top off my tank which was on 3/4. truck ran great about 2 weeks ago the last time I drove it. Yesterday, it was hard to keep it running even choked at higher rpm. Seemed to really hesitate under load, but would stall sitting still. Also really really hard to start. I'm stumped. Greatly appreciate any help.