My battery was replaced in February this year when I got it serviced, so it shouldn't be that. Whenever it rains or if it is humid and misty my engine seems to lose power, it will start but then randomly jerk and jitter under low and high speeds/revs. When I try to correct it by pushing on the accelerator to increase the revs the rev meter will continue to drop and then suddenly increase giving lots of revs for half a second then decrease again making it jittery and hard to drive. ONLY experienced it in bad/wet weather conditions. The battery warning light flickers wildly when the power is decreasing and when the revs shoot back up again it goes off. Any advice is much appreciated.