increased emissions code
I've got an issue that is scaring me in my 2005 645ci 175k miles! It has no mufflers. Was straight piped past the catalytic converters "Ca." I am throwing p0491 codes and other random misfires. I brought it in and the shop diagnosed it as a bad battery.. ? Made sense to me sorta.. they charged me over $300.. light came back on. I pulled a spark plug on cyl 1 and it had lots of white build-up. I'd like to not keep throwing money at this. Also I lose a bit of coolant somewhere. Haven't seen any drip, but the shop also sailed there was coolant residue in places. Would the thermostat and a tune-up possibly help?