Engine jerking on 2004 Mazda MPV

The engine was jerking sometimes when I drive my mpv but not at idle.

Asked by for the 2004 Mazda MPV
No check engine light?
If the light's on, the light indicates that the computer has detected a malfunction in the engine/transmission control system and has diagnostic codes and data stored which would be essential in diagnosing the problem.
A technician with a scanner can access the diagnostic codes and data and then be able to give you a diagnosis.
If no light, check out the ignition system. I think that misfire under load is usually poor ignition.
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