thanks for the further input and ideas.

this is why i like this forum-your feedback is very useful.

haasman,

the spark plugs are of the BERU brand -14k-7duo (which is the equivalent of bosch-h7dco).

azhari,

no misfire at idle-hence the fuel pump is a possibility as it is noisy on an intermittent basis.alos the jerking is intermittent-none of it recently-