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2001 Chevrolet Impala consuming more gas after misfire

So she misfired in the rain about a month ago. They said there was a misfire but that he couldn’t see any reason why it misfired. So then today on another heavy rain I was driving and I sped up on the interstate and it started jumping and so I slowed down kept it around 60 the car ran fine but it was sucking gas probably using double the amount that it should, I get about 20 minutes down the road & raw gas fumes started coming inside the car?

You are making me assume “she” means the car and “they” is an auto repair shop.

Now you have a bigger problem than a simple misfire and maybe the shop can now find the problem, especially if the yellow check engine light is on. I can’t offer any more help not knowing anything more than it is a 2001 Impala.

It sounds like the engine is still misfiring. More specifically, it sounds like it tends to misfire when it is raining. The raw gas smell and the higher fuel consumption would go along with the misfiring engine. A good shop (or even a parts store maybe) should be able to scan for codes. If the misfires can be traced to a certain cylinder, I’d suggest inspecting or possibly replacing the coil, plug, and/or plug wires for that cylinder. Replace the cheapest items first (plugs and wires).

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Was the check-engine light on when this happened? Was it solid or flashing?

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A misfire that bad ought to make the CEL flash, no? Maybe the CEL does not work at all. That can be verified by turning the key to Run and inspect the instrument panel lights and gauges.

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Okay thank you!

It’s always on because I had a catalytic converter put on it that apparently was for a different car many years ago. But the first time yes it was flashing. This second time no it wasn’t.

It did flash the first time. They looked it over & this time when the smell occurred & the sputtering it didn’t flash

What? Nobody pulled any trouble codes (DTCs Diagnostic trouble codes)?

Although I usually never suspect spark plug wires on GM vehicles, I suspect a bad plug or plug wire(S) in this case. I own an 01 Impala.

A DTC would pinpoint the offending cylinder(s) or indicate a general misfire.

:palm_tree: :sunglasses: :palm_tree:

I ALWAYS suspect plug wires on GM vehicles

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Another idea: Sometimes a misfire will cause a sort of reverse backfire into the intake manifold. When that occurs it can upset stuff connected to the intake manifold. I had that happen on my VW Rabbit one time, and it caused the idle air control gadget to go out of whack. In your case the misfire could have damaged the MAP for example, which could affect fuel economy and performance. It could also loosen a vacuum hose enough to allow an air leak in the intake path, definitely a potential cause for increased gasoline usage.

A flashing check-engine light means that you need to stop driving right away to avoid damage to other components such as your catalytic converter. If you’re saying that you kept driving, keep your fingers crossed.

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