Safe to drive 99 Grand Am????

We have a 99 Pontiac Grand Am with 99K miles and it has been using coolant for about a month now.
Adding coolant only seems to have prolonged the inevitable.
Now it used 1/2 gallon for the last 30 miles and the service engine light has come on. The car also is running poorly. It is missing badly. I want to take it to AutoZone to get a diagnostics. Is it safe to drive? Any idea why it is now missing? The oil is clean and exhaust appears OK.
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Keyser Soze wrote:

Blown head gasket.
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Look around the thermostat Housing and see of there is water there.
If so change the thermostat Gasket and add stop leek to Engine
If no water there probably intake manifold gasket,

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yes head gasket

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I should mention the car has a 3.4 liter V6 which is known for intake exhaust gasket problems.
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Forget the code, where is the coolant going? If this is a 3.1 or 3.4, the intake manifold gaskets are known to be a problerm, if that coolant is getting intop the engine, stop driving it asap.

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It's a 3.4. The coolant appears to be exiting outside of the engine. Researching the 3.4 and intake gasket problems suggests that coolant entering into into a cylinder from a faulty gasket is nearly impossible. Oil and exhaust appear clean.
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So you see coolant on the engine, where? Pressure test it and see where it is coming from. You made it sound like the coolant is disappearing, with no external trace?

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Guessing and groping for answers never matches testing and diagnosing. Where do you suppose that new engine misfire is coming from? Maybe looking at a plug would help. The sad news is that in prolonged cases like this where a person insists on topping off and driving a vehicle with a coolant leak, the damage often becomes progressive and the repair more complicated. Then a partial repair is soon followed by subsequent repairs because of a partial guess diagnosis to begin with.
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You failed to read the posts by people who had the cams freeze and break and those that had to have the engine replaced. Since you are apparently not a mechanic take it in and have it fixed. This usually is not a DIY project unless you have good mechanical skills. If you keep driving it make sure you carry a cell phone and the number of a towing service....

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Geez we've all basically said the same thing here, which in fact should have been unnecessary to begin with!!!

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I have read the posts about camshaft damage and was led to believe that the 3.8L engine is prone to that failure. I checked the oil and have not seen any trace of coolant.
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