Can driving with misfire cause engine damage?

Maintenance/Repairs
1

Title. Can driving with single cylinder misfire due to lean condition cause major engine damage and if so what? (Piston rings, valve stems, etc.) I have a misfire on cylinder 3 on my 4 cyl car for the first 1-2 minutes of driving then it goes away. What damage do I risk to my engine if any if I continue to drive it like this? Mechanic said car probably has a weak fuel pump. My funds may not allow me to fix the issue for another couple weeks

2

A mis fire puts unburned fuel in the exhaust and can overheat and damage the catalytic converter.

Try another mechanic, I doubt a weak fuel pump would cause a misfire consistently on the same cylinder.

BTW is this a 1968 Cortina with 145,000 miles?

How about telling us what the car is, make, model, year, mileage, maintenance history etc.

3

What if the misfire is because an injector isn’t injecting fuel?

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4

It’s not perfect, but most manuals tell you to shut off the engine if the CEL is blinking, to avoid doing damage; but driving with the light on is OK.

You might have leaking injector. Pour a bottle of Techron cleaner into your gas and give it some time and miles to maybe clear up the problem.

5

Is that what the “lean condition” means? I’d think too little fuel wouldn’t necessarily mean none.

6

It might. Cat at risk. Also could overheat and damage valve etc. Could be benign for the most part too. Best to get it diagnosed asap imo.

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7

A bad fuel pump would cause a misfire on all cylinders randomly, not just one cylinder.
Likely causes:
Intake manifold gasket
Fuel injector
Fuel injector wire (personal experience with this one)

How do you know it’s a misfire due to a lean condition?

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8

“Lean” means that there is either too much air or not enough fuel. Instead of replacing parts, this can likely be diagnosed quickly by checking fuel trim values on a scan tool with live data. You may also have more than one issue, like a bad spark plug and a vacuum leak for example.

9

Again, “lean” doesn’t necessarily mean no fuel. It means an improper mixture. I agree with @Dappersworth that it’s not the fuel pump. Bad or leaking injector is more likely.

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