Recently, my car started overheating really badly, and shaking, both while driving and in idle. Any Ideas as to what this could be? Oh, and my car is a 2004 BMW.
Check the oil for signs of coolant contamination, if it looks milky. Your describing a classic blown head gasket.
What was your coolant level when you checked it?
If it does turn out to be a breached head gasket, you will definitely NOT think that it is cool…especially when you see the potential repair bill.
Just for future reference, at the first sign of overheating, you should have had the car towed to a competent mechanic’s shop. By apparently continuing to drive it, you have almost surely increased the damage and the repair bill–which can be astronomical on a BMW.
If your car was…let’s say…a '48 Plymouth, it could probably withstand repeated overheating incidents w/o too much risk of damage. However, on modern vehicles, overheating can quickly lead to the destruction of the engine.
All of that being said, I hope for your sake that the head gasket is not breached.
And, it is possible that there are two separate problems leading to overheating and poor engine performance.
Just for the sake of discussion and diagnosis of the engine performance issue…
Is the Check Engine Light lit up, or is it flashing?
Is the car 100% up to date with its maintenance?