engine hiccup, does not die, but it sputters Options

[malcolm2]

75 L-jet 1911cc engine. Last problem was solved in May I believe. I have been putting miles on it pretty regularly since then.

Some folks may remember that I had an internal backfire and bent my AFM. The backfire came from a massive vacuum leak at the TB seal. I had just had the TB rebuilt, but did not replace the seal and did not install it in the same orientation as it was before. So there were depressions on the seal. Anyway. My smoke machine found the leak, plus a few more. Sealed them up and installed a new AFM tuned to the 1911 and all was well.

Fast forward to this week. Wednesday driving home from work, just entering the interstate and I got a big hiccup. Felt like the engine died for a brief second as I was shifting. Kinda like the jerk you feel when you are jump starting the car by popping the clutch.

made it home and did not drive again 'til this morning. It happened again. Then again, then really bad spitting and sputtering on acceleration. It idles fine tho. So I turned around and went home. Smooth ride home to get another car, thank goodness.

I have an on board Air/Fuel meter that I have been monitoring. All this happens so quickly, I just don't have time to see the meter.

1/2 a tank of gas, just e10 87 oct, but it could be bad. But the 1st 1/2 was fine.

I figure if I can this weekend, I'll breakout the smoke machine and see it I have another vacuum leak.

Any other thoughts.