my megane shudders when revved up,any idea?

when revving up to change gear,my renault megane shudders violently.I've changed spark plugs + the 4 coil packs.also the dashboard lights dim,the petrol light blinks on.the milometer resets. My renault is a megane classic,1999.I've reverted to changing gear early to minimise the shudder.Any idea?
Phil, March 2006


done
could be the ignition coils one of which may have burned out

OCTAVIUS LEWIS, November 2010
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