Check your crankshaft reluctor wheel!

Those kind of things can drive you crazy, trying to find; unless you have a way to capture signals / flight record the events, as they happen; and even then, you may not see anything. I had one of the cam gears work loose (similar to your issue), on a DOHc V-6. Normal driving - no issues. Try to accelerate hard- it threw codes that didn't make sense, including ABS codes. Talk about tail chasing...