Don’t feel bad, I had this annoying front end thunk that I chased for a year. Changed lower ball joint, lower control arm bushing. No change! Finally got the wife in the car to turn the wheel a little back and forth while I watched. Out of the corner of my eye I see the k frame move just a hair. All four bolts had back off to finger tight! Doh! I remember thinking when I tightened them the first time “These are forty year old rusty threads that would be a diaster if you strip them!” This time, IMPACT!