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Q: Bad gas in tank of 1994 Pontiac Bonneville

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My car won't go over 30 MPH. The battery failed and I had to replace it. The part store said the alternator and starter are good, but I still can't get it to go over 30 to 40 MPH. The other day I heard sounds coming out of the tailpipe, along with some white to light gray smoke. My first thought was I had put in some bad gas as my problems started when I filled up at a local gas station. I added fuel injector cleaner while I was at the auto parts store.

A: The first thing I would check would be for ...

The first thing I would check would be for codes on the computer. If there are no codes present you could have a clogged catalytic converter. This is where the honeycomb inside the catalytic converter becomes so clogged that it will not allow exhaust gas to pass through it bogging down the engine. The white smoke coming from the tailpipe could indicate a blown head gasket. This is where the car overheats and warps the head and causes water to pass by the gasket getting into the engine. Your car would probably run very rough if this were the case. A leak down test can be performed to check and see if in fact you do have a blown head gasket by a qualified technician.

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