Hi 1.6 petrol 2004, Car was idling lumpy this morning and revs were low, took car for 15 mile trip and it drove fine. But after 1/2 hour away it wouldn't start just like it had a flat battery all the dash lights worked but not enough juice to turn the engine. So i had to walk and get a set of jump leads when i got back ( about 15 mins ) i tried the ignition again just to make sure and it started. drove home and checked battery connections they were all fine but it still runs lumpy and low revs about 600rpm, also the exhaust is putting out grey/white fumes. i put the battery on charge just to be sure and when i re-connected after about 5 hours charge it is now idiling correct. Any ideas suggestions welcome thanks.