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1997 malibu issues

Alright, when I first crank the car I get a thump on the passenger side. Sounds like somthing to do with the a/c. It’s having multiple misfires and dies at idle when I stop at a red light. It idles horrible all the time. It acts differently depending on how much gas is in it. If its full it runs great but as soon as it hits 3/4 of a tank it all goes down hill and starts shaking. The low coolant light flicks on and off too. The coolant has been going pretty fast out of the reserve tank. I had the radiator flushed and it helped with that a little bit. I replaced spark plugs and the temperature sensor already. What is my next move? Or what does it sound like?

If you are loosing coolant you have a leak. If you over heat serious engine damage can occur. You do not have a low coolant light, that light most likely means your engine temp is to high.

It sounds like you have an internal engine leak that is shorting out the spark plugs. Unless you quickly find the cause and correct it you engine will be toast. I suspect a head gasket breech.

Find the cause of the coolant loss as your first priority.

I absolutely agree that the first thing you have to do is diagnose the coolant loss. And, as suggested, I suspect you’ll also find the cause of the other problems.

Here are a couple of “quick check” ways to tell if you have a headgasket leak.
With the system cool, run the engine with the radiator cap off. If the coolant is bubbling in the radiator, that’ll be combustion gasses bypassing a breeched headgasket into the water jacket and migrating to the system’s highest point: the fill hole.

You could also do a simple and inexpensive chemical test of the coolant for the presence of hydrocarbons. Hydrocarbons would be coming from the combustion process. The kit will come with instructions.

A better check is a pressure leakdown test of the cylinders. But, in all honesty, it the other two tests fail, that’ll only be confirmation.

You need to address this ASAP. It’s a condition that will cause more and more damage as it continues… and the cost to repair the damages will rise correspondingly. It is not an inert problem that can be left for a later time.

Post the results. We do care.

If this has the 3.1 L engine you probably have a bad intake manifold gasket. This engine is famous for this.

Rockauto lists a “coolant level sensor” for your car so you probably have that warning light. With a cool engine, check coolant level in the radiator itself. These level sensors were known for going bad and are no longer used.

Is your check engine light on? Have you read the codes?