I had a problem with a 99 olds intrigue 'babystar' (V6) that 'jolted' when you had it under a full load (A/C and loaded, hard acceleration). Turns out two of the three 'dual' coils on the top of the motor was 'open' on their secondaries internally. After finding that I purchased two modules (of the three) and never a problem again. The 'jolt' was the result of the cylinder not burning the fuel/air for its cycle. Now since the spark was successfully 'jumping' the gap in those 'opens' AND the tip of the plug, then could it be possible the sensors never tripped (code) due to the fact it was of such a short duration? I have never pulled a coil pack off these engines, but wonder IF your having this 'jolt' (buck) due to a coil pack being open on the secondary? I would take the coils out one at a time (circuit test) and see if the high voltage side is open. I would think the low voltage side would 'trip' a code, but there is no 'code' trip-able for a coil secondary being 'open' (or IS there BESIDES a fully open larger gap preventing ANY spark reaching the plugs that would trip a misfire)? Just a thought, it should be quite easy to see if your coils are open on their respective secondaries. Have not pulled the manual out because I would think the schematics would not show the internal wiring of the coil packs. Since they are 'dual' coils, you might have to test (continuity) each to ground (OR) each 'tip' to 'tip'. IF they all read the same (tip to tip and each tip to a common ground), then I would guess they are OK. It would take a little time, but you have had a lot of downtime with the car anyway right?

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