Weird start-up

[Mariach]

So, I got into the Pathy this morning, and started her up, and I saw smoke comming from the tail pipe, as well as a weird rumbling. It was shaking so hard that the seatbelts were rattling.

It's not the first time I have seen the smoke, a few times when sitting at a light I see it behind me. It's always a thick white smoke, not blueish white or dark at all. Like cigarette smoke.

I have heard it can be either the engine running too rich, a blown head gasket or cracked block?

[Pwnin O'Brien]

Does the thick white smoke have a smell to it? If it has a sweeter smell, and a slight smell of coolant, than it is coolant leaking into a cylinder. If it is really thick smoke, then you would want to check the coolant level. Really thick white smoke means you are burning through a lot of coolant. If the car were running that rich, it would most likely throw an oxygen sensor error code.

If you open the oil filler cap, is there any foam around the underside of the cap? Anything other than oil? While it's common coolant will get into the oil system on a cracked block or head gasket, it's not guaranteed.

Your best bet is to acquire a coolant system pressure checker as well as a cylinder compression checker to diagnose where the crack is.

[Mariach]

Nothing in the oil... the smoke smells kinda rancid... like something dead on fire.

[Pwnin O'Brien]

Is it a rotten egg smell? That's usually indicative of high sulfur fuel or failing catalytic converters. I doubt it's a failing catalytic converter because the ECM would likely pick that up and throw an error.

If your coolant levels are normal, I would probably recommend buying fuel from a different supplier. If that still doesn't solve the problem, the your car may be running extremely rich and the ECM just hasn't picked up on it.