therongober

I've got a 2005 A4 that has a rough idle on cold start. When we clear the codes by disconnecting the battery the car starts fine and drives fine but then the next morning it starts rough again. The car is giving the following codes:

16684 - Random / Multiple Cylinder misfire detected PO300 - 001 0- Intermittent
16686 Cylinder 2 PO302-001 - Misfire detected Intermittent
16687 Cylinder 3 PO303-008 - Misfire detected intermittent
16685 Cylinder 1 PO301- 008 - Misfire detected intermittent
18010 - Power supply terminal 30 P1602 -002 Voltage too low - intermittent

I've been dealing with this for weeks and have changed all the spark plugs, coil packs, throttle body, air filter.
Any ideas would be greatly appreciated.

therongober

The car is now hard to start in addition to the rough idle and has been drinking coolant but there is no sign of coolant in the oil and there doesn't appear to be a leak but maybe there is one while driving that we haven't noticed...

v_dubbin

Sounds like a head gasket.
Missing coolant and misfire almost guarantees it. The coolant usually doesnt go in the oil it goes in the cylinder and burns out the exhaust as steam.